Association between endotoxemia and blood no in the portal circulation of cirrhotic patients: results of a pilot study

Pathophysiology of portal vein thrombosis (PVT) in cirrhosis is still not entirely understood. Elevated levels of lipopolysaccharides (LPS) in portal circulation are significantly associated with hypercoagulation, increased platelet activation and endothelial dysfunction. The aim of the study was to investigate if LPS was associated with reduced portal venous flow, the third component of Virchow's triad, and the underlying mechanism. Serum nitrite/nitrate, as a marker of nitric oxide (NO) generation, and LPS were measured in the portal and systemic circulation of 20 patients with cirrhosis undergoing transjugular intrahepatic portosystemic shunt (TIPS) procedure; portal venous flow velocity (PVV) was also measured in each patient and correlated with NO and LPS levels. Serum nitrite/nitrate and LPS were significantly higher in the portal compared to systemic circulation; a significant correlation was found between LPS and serum nitrite/nitrate (R = 0.421; p < 0.01). Median PVV before and after TIPS was 15 cm/s (6-40) and 31 cm/s (14-79), respectively. Correlation analysis of PVV with NO and LPS showed a statistically significant negative correlation of PVV with portal venous NO concentration (R = - 0.576; p = 0.020), but not with LPS. In vitro study with endothelial cells showed that LPS enhanced endothelial NO biosynthesis, which was inhibited by L-NAME, an inhibitor of NO synthase, or TAK-242, an inhibitor of TLR4, the LPS receptor; this effect was accomplished by up-regulation of eNOS and iNOS. The study shows that in cirrhosis, endotoxemia may be responsible for reduced portal venous flow via overgeneration of NO and, therefore, contribute to the development of PVT.

Gut barrier dysfunction and endotoxemia in heart failure: A dangerous connubium?

Heart failure (HF) is a leading cause of death worldwide despite recent advances in pharmacological treatments. Gut microbiota dysbiosis and gut barrier dysfunction with consequent bacterial translocation and increased blood endotoxemia has gained much attention as one of the key pathogenetic mechanisms contributing to increased mortality of patients at risk or with cardiovascular disease. Indeed, increased blood levels of lipopolysaccharide (LPS), a glycolipid of outer membrane of gut gram-negative bacteria, have been detected in patients with diabetes, obesity and nonalcoholic fatty liver disease or in patients with established coronary disease such as myocardial infarction or atrial fibrillation, suggesting endotoxemia as aggravating factor via systemic inflammation and eventually vascular damage. Upon interaction with its receptor Toll-like receptor 4 (TLR4) LPS may, in fact, act at different cellular levels so eliciting formation of proinflammatory cytokines or exerting a procoagulant activity. Increasing body of evidence pointed to endotoxemia as factor potentially deteriorating the clinical course of patients with HF, that, in fact, is associated with gut dysbiosis-derived changes of gut barrier functionality and eventually bacteria or bacterial product translocation into systemic circulation. The aim of this review is to summarize current experimental and clinical evidence on the mechanisms linking gut dysbiosis-related endotoxemia with HF, its potential negative impact with HF progression, and the therapeutic strategies that can counteract endotoxemia.

PAD4-Induced NETosis Via Cathepsin G-Mediated Platelet-Neutrophil Interaction in ChAdOx1 Vaccine-Induced Thrombosis-Brief Report

BACKGROUND

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare syndrome characterized by platelet anti-PF4 (platelet-activating antiplatelet factor 4)-related thrombosis. Platelet-neutrophil interaction has been suggested to play a role, but the underlying mechanism has not been fully elucidated.

METHODS

The study included 10 patients with VITT after ChAdOx1 (chimpanzee adenovirus Oxford 1) nCoV-19 (Oxford-AstraZeneca) vaccine administration, 10 patients with ischemic stroke (IS), 10 patients with acute deep vein thrombosis, and 10 control subjects in whom blood levels of neutrophil extracellular traps (NETs), soluble TF (tissue factor), and thrombin generation were examined. Furthermore, we performed in vitro studies comparing the effect of serum from patients and controls on NETs formation. Finally, immunohistochemistry was performed in cerebral thrombi retrieved from a patients with VITT and 3 patients with IS.

RESULTS

Compared with patients with IS, patients with deep vein thrombosis, controls, and patients with VITT had significantly higher blood values of CitH3 (citrullinated histone H3), soluble TF, D-dimer, and prothrombin fragment 1+2 (P<0.0001). Blood CitH3 significantly correlated with blood soluble TF (Spearman rank correlation coefficient=0.7295; P=0.0206) and prothrombin fragment 1+2 (Spearman rank correlation coefficient=0.6809; P<0.0350) in patients with VITT. Platelet-neutrophil mixture added with VITT plasma resulted in higher NETs formation, soluble TF and thrombin generation, and platelet-dependent thrombus growth under laminar flow compared with IS and deep vein thrombosis plasma; these effects were blunted by PAD4 (protein arginine deiminase 4) and cathepsin G inhibitors, anti-FcγRIIa (Fc receptor for IgG class IIa), and high doses of heparin. Immunohistochemistry analysis showed a more marked expression of PAD4 along with more diffuse neutrophil infiltration and NETs formation as well as TF and cathepsin expression in VITT thrombus compared with thrombi from patients with IS.

CONCLUSIONS

Patients with VITT display enhanced thrombogenesis by PAD4-mediated NETs formation via cathepsin G-mediated platelet/neutrophil interaction.

Dark Chocolate Intake Positively Modulates Gut Permeability in Elite Football Athletes: A Randomized Controlled Study

Gut barrier disruption can lead to enhanced intestinal permeability, which allows endotoxins, pathogens, and other proinflammatory substances to move through the intestinal barrier into circulation. Intense exercise over a prolonged period increases intestinal permeability, which can be further worsened by the increased production of reactive oxygen species (ROS) and pro-inflammatory cytokines. The aim of this study was to assess the degree of intestinal permeability in elite football players and to exploit the effect of cocoa polyphenols on intestinal permeability induced by intensive physical exercise. Biomarkers of intestinal permeability, such as circulating levels of zonulin, a modulator of tight junctions, occludin, a tight junction protein, and LPS translocation, were evaluated in 24 elite football players and 23 amateur athletes. Moreover, 24 elite football players were randomly assigned to either a dark chocolate (>85% cocoa) intake (n = 12) or a control group (n = 12) for 30 days in a randomized controlled trial. Biochemical analyses were performed at baseline and after 30 days of chocolate intake. Compared to amateur athletes, elite football players showed increased intestinal permeability as indicated by higher levels of zonulin, occludin, and LPS. After 30 days of dark chocolate intake, decreased intestinal permeability was found in elite athletes consuming dark chocolate. In the control group, no changes were observed. In vitro, polyphenol extracts significantly improved intestinal damage in the human intestinal mucosa cell line Caco-2. These results indicate that chronic supplementation with dark chocolate as a rich source of polyphenols positively modulates exercise-induced intestinal damage in elite football athletes.

Diverticular Disease Worsening Is Associated with Increased Oxidative Stress and Gut Permeability: New Insights by Circulating Biomarkers

Diverticular disease (DD) management is impaired by its pathogenesis, which is still not completely defined, with an unmet clinical need for improved therapies. Ex vivo DD human models demonstrated the presence of a transmural oxidative imbalance that supports an ischemic pathogenesis. This study aimed to assess, with the use of circulating biomarkers, insights into DD pathogenesis and possible therapeutic targets. Nox2-derived peptide, H2O2, antioxidant capacity, isoprostanes, thromboxanes, TNF-α, LPS and zonulin were evaluated by ELISA in healthy subjects (HS) and asymptomatic and symptomatic DD patients. Compared to HS, DD patients presented low antioxidant capacity and increase in sNox2-dp, H2O2 and isoprostanes paralleled to a TNFα increase, lower than that of oxidative markers. TxB2 production correlated to Nox2 and isoprostanes, suggesting platelet activation. An increase in zonulin and LPS highlighted the role of gut permeability and LPS translocation in DD pathogenesis. The increase of all the markers statistically correlated with DD severity. The present study confirmed the presence of a main oxidative imbalance in DD and provides evidence of platelet activation driven by LPS translocation. The use of circulating biomarkers could represent a new clinical tool for monitoring disease progression and validate therapeutic strategies never tested in DD as antioxidant supplementation.

Gut dysbiosis-derived low-grade endotoxemia: A common soil for liver and cardiovascular disease

Gut dysbiosis is characterized by bacteria overgrowth that ultimately leads to increased intestinal barrier permeability and bacteria or bacteria product translocation such as lipopolysaccharide (LPS) in the portal and eventually systemic circulation. Intestinal epithelial cells and hepatocytes encompass enzymatic armamentarium to counteract the LPS toxic effect, however impaired degradation results in LPS accumulation in hepatocytes and endothelial wall. Experimental and clinical study documented that in patients with liver disease, such as non-alcoholic fatty acid liver disease (NAFLD), low-grade endotoxemia by LPS is implicated in liver inflammation and thrombosis via interaction with its Toll-like receptor 4 (TLR4) expressed by hepatocytes and platelets. Furthermore, studies in patients with severe atherosclerosis documented that LPS localizes into atherosclerotic plaque in close association with activated macrophages expressing TLR4 suggesting a role for LPS in vascular inflammation, atherosclerotic progression, and thrombosis. Finally, LPS may directly interact with myocardial cells to induce electric and functional changes leading to atrial fibrillation or heart failure. This review will focus on experimental and clinical evidence suggesting low-grade endotoxemia as mechanism potentially accounting for vascular damage occurring at level of hepatic and systemic circulation and myocardial cells.

Toll-Like Receptor 4-Dependent Platelet-Related Thrombosis in SARS-CoV-2 Infection

BACKGROUND

SARS-CoV-2 is associated with an increased risk of venous and arterial thrombosis, but the underlying mechanism is still unclear.

METHODS

We performed a cross-sectional analysis of platelet function in 25 SARS-CoV-2 and 10 healthy subjects by measuring Nox2 (NADPH oxidase 2)-derived oxidative stress and thromboxane B₂, and investigated if administration of monoclonal antibodies against the S protein (Spike protein) of SARS-CoV-2 affects platelet activation. Furthermore, we investigated in vitro if the S protein of SARS-CoV-2 or plasma from SARS-CoV-2 enhanced platelet activation.

RESULTS

Ex vivo studies showed enhanced platelet Nox2-derived oxidative stress and thromboxane B₂ biosynthesis and under laminar flow platelet-dependent thrombus growth in SARS-CoV-2 compared with controls; both effects were lowered by Nox2 and TLR4 (Toll-like receptor 4) inhibitors. Two hours after administration of monoclonal antibodies, a significant inhibition of platelet activation was observed in patients with SARS-CoV-2 compared with untreated ones. In vitro study showed that S protein per se did not elicit platelet activation but amplified the platelet response to subthreshold concentrations of agonists and functionally interacted with platelet TLR4. A docking simulation analysis suggested that TLR4 binds to S protein via three receptor-binding domains; furthermore, immunoprecipitation and immunofluorescence showed S protein-TLR4 colocalization in platelets from SARS-CoV-2. Plasma from patients with SARS-CoV-2 enhanced platelet activation and Nox2-related oxidative stress, an effect blunted by TNF (tumor necrosis factor) α inhibitor; this effect was recapitulated by an in vitro study documenting that TNFα alone promoted platelet activation and amplified the platelet response to S protein via p47phox (phagocyte oxidase) upregulation.

CONCLUSIONS

The study identifies 2 TLR4-dependent and independent pathways promoting platelet-dependent thrombus growth and suggests inhibition of TLR4. or p47phox as a tool to counteract thrombosis in SARS-CoV-2.

Gut dysbiosis, endotoxemia and clotting activation: A dangerous trio for portal vein thrombosis in cirrhosis

Liver cirrhosis (LC) is associated with portal venous thrombosis (PVT) in roughly 20% of cirrhotic patients but the underlying mechanism is still unclear. Low-grade endotoxemia by lipopolysaccharides (LPS), a component of outer gut microbiota membrane, is detectable in the portal circulation of LC and could predispose to PVT. LPS may translocate into systemic circulation upon microbiota dysbiosis-induced gut barrier dysfunction, that is a prerequisite for enhanced gut permeability and ensuing endotoxemia. Experimental and clinical studies provided evidence that LPS behaves a pro-thrombotic molecule so promoting clotting and platelet activation. Experiments conducted in the portal circulation of cirrhotic patients showed the existence of LPS-related enhanced thrombin generation as well as endothelial dysfunction, venous stasis, and platelet activation. The review will analyze 1) the pro-thrombotic role of endotoxemia in the context of LC 2) the biological plausibility linking endotoxemia with PVT and 3) the potentially interventional tools to lower endotoxemia and eventually hypercoagulation.

High Compliance to Mediterranean Diet Associates with Lower Platelet Activation and Liver Collagen Deposition in Patients with Nonalcoholic Fatty Liver Disease

The Mediterranean diet (Med-Diet) is considered the most effective dietary patterns to obtain weight loss in NAFLD patients. Previous evidence suggested that Med-Diet adherence could reduce cardiovascular risk and have a beneficial effect on NAFLD severity. Aim of the study was to investigate the relationship between Med-Diet adherence, platelet activation (PA), and liver collagen deposition. The study was performed in 655 consecutive NAFLD outpatients from the PLINIO study, a prospective observational cohort study aimed to identify non-conventional predictors of liver fibrosis progression in NAFLD. PA was measured by the serum thromboxane B2 (TxB2), and liver collagen deposition by N-terminal propeptide of type III collagen (Pro-C3). Adherence to the Med-diet was investigated by a short nine-item validated dietary questionnaire. Patients with high Med-Diet adherence were older and had less metabolic syndrome and lower serum triglycerides, GGT, TxB2, and Pro-C3. At multivariate regression analyses, in the linear model, the Med-Diet score negatively correlated with both TxB2 (Beta = −0.106; p = 0.009) and Pro-C3 (Beta = −0.121; p = 0.002) and in the logistic model high adherence inversely correlated with higher TxB2 tertiles (II tertile: OR = 0.576, p = 0.044; III tertile: OR = 0.556, p = 0.026) and Pro-C3 tertile (III tertile: OR = 0.488, p = 0.013). Low consumption of red meat inversely correlated with higher TxB2 tertile (II tertile: OR = 0.448, p < 0.001, III tertile: OR = 0.567, p = 0.004). In conclusion, NAFLD patients with high adherence to the Med-Diet show lower PA and liver collagen deposition, suggesting a protective role of the Med-Diet against NAFLD progression and cardiovascular risk. In addition, the correlation between TxB2 and Pro-C3 suggests a link between NAFLD severity and cardiovascular risk.

Circulating Lipopolysaccharides and Impaired Antioxidant Status in Patients With Atrial Fibrillation. Data From the ATHERO-AF Study

Objectives: Atrial fibrillation (AF) is characterized by an oxidative imbalance, which is associated with an increased risk of cardiovascular events (CVEs). It is unclear whether low grade endotoxemia may contribute to the impaired antioxidant status in AF patients. We investigated the relationship between circulating lipopolysaccharides (LPS) and antioxidant status in AF patients.

Patients and Methods:Post-hoc analysis from the ongoing prospective observational cohort ATHERO-AF study including 907 patients. Antioxidant status was evaluated by the activity of glutathione peroxidase 3 (GPx3) and superoxide dismutase (SOD). Patients were divided into two groups to evaluate the risk of CVEs: (1) LPS below median and GPx3 above median (n = 254); (2) LPS above median and GPx3 below median (n = 263).

Results: The mean age was 73.5 ± 8.3 years, and 43.1% were women. Median LPS and GPx3 were 50.0 pg/ml [interquartile range (IQR) 15–108] and 20.0 U/ml (IQR 10.0–34.0), respectively. Patients of Groups 2 were older, with a higher prevalence of heart failure. LPS above the median was associated with reduced GPx3 [Odds Ratio for LPS 1.752, 95% Confidence Interval (CI) 1.344–2.285, p < 0.001] and SOD (OR 0.525, 95%CI 0.403–0.683) activity after adjustment for CHA₂DS₂VASc score. In a mean follow-up of 54.0 ± 36.8 months, 118 CVEs occurred, 42 in Group 1 and 76 in Group 2 (Log-Rank test p = 0.001). At multivariable Cox regression analysis, Group 2 was associated with a higher risk of CVEs [Hazard Ratio (HR) 1.644, 95%CI 1.117–2,421, p = 0.012], along with age ≥ 75 years (HR 2.035, 95%CI 1.394–2.972, p < 0.001), diabetes (HR 1.927, 95%CI 1.280–2.900, p = 0.002), and previous cerebrovascular disease (HR 1.895, 95%CI 1.251–2.870, p = 0.003) and previous cardiovascular disease (HR 1.708, 95%CI 1.149–2.538, p = 0.008).

Conclusions: Our study indicates that circulating LPS may contribute to impaired antioxidant status in patients with AF. Patients with coincidentally high LPS and reduced GPx3 activity showed the highest risk of CVEs.

Chocolate enriched by extra virgin olive oil improves endothelial function and oxidative stress in patients with diabetes

OBJECTIVE

Endothelial dysfunction and oxidative stress are among the most relevant mechanisms underlying the atherosclerotic process in patients with type 2 diabetes mellitus (T2 DM). Extra virgin olive oil (EVOO) reduces postprandial glycemia with a mechanism counteracting oxidative stress-mediated incretin down-regulation in healthy subjects and in patients with impaired fasting glucose. The aim of this study was to evaluate if the intake of chocolate enriched by EVOO had positive effects on endothelial function and oxidative stress in patients with T2 DM.

METHODS

In this study we enrolled and randomly assigned 25 consecutive patients with T2 DM to receive 40 g of EVOO-enriched chocolate or 40 g of control chocolate spread. Participants were assessed at baseline and 2 h after chocolate intake. Endothelial function was assessed by arterial brachial flow-mediated dilation (FMD); oxidative stress was evaluated by the measurement of serum nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-2 (Nox2) levels, nitric oxide availability, and serum hydrogen peroxide breakdown activity (HBA).

RESULTS

We observed a significant increase of FMD, nitric oxide (NO) availability, and HBA in the EVOO-enriched chocolate group (P < 0.001). Conversely, soluble Nox2-derived peptide (sNox2-dp) levels significantly decreased (P < 0.001). No significant change was observed in the control chocolate group. To assess the relation of EVOO-enriched chocolate to endothelial function and oxidative stress, a general linear model (GLM) analysis was performed; a significant difference for treatments was found with respect to FMD, NO availability, HBA, and sNox-dp.

CONCLUSIONS

Administration of 40 g of EVOO-enriched chocolate is associated with increased endothelial function and reduction of oxidative stress in patients with T2 DM. Future studies are needed to analyze the effect of chronic assumption of EVOO-enriched chocolate on vascular function, oxidative stress, and cardiovascular complications in patients with T2 DM.

The Role of Antioxidants Supplementation in Clinical Practice: Focus on Cardiovascular Risk Factors

Oxidative stress may be defined as an imbalance between reactive oxygen species (ROS) and the antioxidant system to counteract or detoxify these potentially damaging molecules. This phenomenon is a common feature of many human disorders, such as cardiovascular disease. Many of the risk factors, including smoking, hypertension, hypercholesterolemia, diabetes, and obesity, are associated with an increased risk of developing cardiovascular disease, involving an elevated oxidative stress burden (either due to enhanced ROS production or decreased antioxidant protection). There are many therapeutic options to treat oxidative stress-associated cardiovascular diseases. Numerous studies have focused on the utility of antioxidant supplementation. However, whether antioxidant supplementation has any preventive and/or therapeutic value in cardiovascular pathology is still a matter of debate. In this review, we provide a detailed description of oxidative stress biomarkers in several cardiovascular risk factors. We also discuss the clinical implications of the supplementation with several classes of antioxidants, and their potential role for protecting against cardiovascular risk factors.

Lipopolysaccharide induces platelet activation in HIV patients: the role of different viral load patterns

OBJECTIVES

This study aimed to assess whether gut-derived lipopolysaccharide (LPS) could affect platelet function in HIV-1 patients with residual viral load.

METHODS

In 23 HIV-1 patients on effective antiretroviral treatment, 10 treatment-naïve HIV-1 subjects and 20 healthy subjects (HS), LPS, zonulin, markers of platelet activation and oxidative stress were evaluated. In vitro, platelets from HS were exposed to plasma from HIV-1-infected treated and untreated patients.

RESULTS

Compared with HS, LPS was higher in treated and treatment-naïve subjects with HIV-1 (7.7 ± 2.9, 80.9 ± 13.7 and 75.3 ± 22.6 pg/mL, P < 0.001 vs. HS) as well as serum zonulin (1.3 ± 0.5, 6.1 ± 1.5 and 5.3 ± 1.7 ng/mL, P < 0.001 vs. HS). LPS and zonulin were correlated in HIV patients (Spearman correlation coefficient (rS) = 0.73, P < 0.0001). Levels of soluble CD40 ligand (sCD40L), soluble P-selectin (sP-selectin) and thromboxane B₂ (TxB₂ ) were higher in HIV-1-treated and treatment-naïve subjects compared with HS as well as NADPH oxidase 2 (NOX2) activation and hydrogen peroxide (H₂ O₂ ) production. In vitro, sCD40L, sP-selectin and TxB₂ production, NOX2 activation and p47^phox phosphorylation were higher in platelets exposed to plasma from HIV-1 patients with different viral load compared with the exposure to plasma from HS. This effect was blunted in platelets pre-treated with TLR4 or TLR7 inhibitors.

CONCLUSIONS

Low-grade endotoxaemia and persistent viraemia increase platelet function with a mechanism mediated by NOX2 in patients with HIV-1 infection.

Environmental impacts of household appliances in Europe and scenarios for their impact reduction

Assessing the environmental impact due to consumption of goods and services is a pivotal step towards achieving the sustainable development goal related to responsible production and consumption (i.e. SDG 12). Household appliances plays a crucial role and should be assessed in a systemic manner, namely considering all life cycle stages, technological efficiency, and affluence aspects. The present study assess the impact of such household appliances used in Europe, and tests scenarios of potential impact reduction at various scales. Life cycle assessment is applied to 14 different household appliances (ranging from dishwashers to television devices) selected to build a set of representative products, based on their economic value and diffusion in households in Europe. Related impacts are calculated with the Environmental Footprint method for calculating a Consumer Footprint "appliances" for the baseline year 2010. A number of scenarios encompassing eco-solutions on a technical level, changes in consumption pattern, behavioral changes, as well as the combination of all these aspects are run to estimate the Consumer Footprint related to household appliances for the year 2030, compared against this baseline scenario. The baseline Consumer Footprint is confirming the importance of the use phase in leading the impacts in almost all impact categories. Testing different scenarios concludes that there is a reduction of the impact for most of the categories (with up to 67% for the ozone depletion potential, and still around 35% for the global warming potential), while two of the here examined impact categories (i.e. land-use and mineral resource depletion) show an overall potential that is even negative - i.e. the results of all scenarios are higher than the ones of the 2010 baseline scenario. The increase in purchase and use of such appliances may offset energy efficiency benefits in some of the examined categories. Hence, the assessment of sustainability of appliances consumption should always include several scales, from the efficiency of the products (micro scale), to the improvement of the energy mix (meso scale), up to accounting for socio-economic drivers and patterns of consumption affecting the overall appliances stock (macro scale).

A novel role of MMP2 in regulating platelet NOX2 activation

NOX2 has a key role for cellular production of reactive oxidant species (ROS) and although the mechanism of its activation is well known, little is known about its regulation. Metallo-proteinases (MMPs) regulate numerous protein activities both in physiological and pathological conditions but their interplay with NOX2 and ROS formation is still unclear. We performed experimental studies in human platelets and polymorphonuclear leukocytes (PMNs) to investigate the interplay of MMP2 with NOX2 activity. In collagen-stimulated platelets and in PMA-stimulated PMNs from healthy subjects, an immediate burst of ROS was detected at 10 min to then decline at 20 min. Coincidentally, sNOX2-dp, a split-off product of NOX2, increased and peaked at 10 min. ROS production was persistent whereas sNOX2dp is not released in cells treated with MMP2 inhibitor compared to other MMPs inhibitors. Western blot analysis showed the highest MMP2 expression on the cell membrane 10 min after stimulation. Moreover, the co-immunoprecipitation assay confirms the interaction between MMP2 and NOX2 that formed an active immuno-complex. Treating cells with NOX2ds-tat, an inhibitor of NADPH oxidase, significantly reduced ROS formation, sNOX2-dp, MMP2 expression and MMP2-NOX2-complex, which were all restored if cells were added with H₂O₂. The study provides the first evidence that MMP2 has a key role in blunting platelet NOX2 activity and eventually ROS formation.

The consumer footprint: Monitoring sustainable development goal 12 with process-based life cycle assessment

Sustainable and responsible production and consumption are at the heart of sustainable development, explicitly mentioned as one of the sustainable development goals (SDG12). Life cycle assessment, with its integrated holistic approach, is considered a reference method for the assessment of the environmental impact of production and consumption. This paper presents a study on the environmental impacts of final consumption in Europe in five areas of consumption: food, mobility, housing, household goods, and appliances. Based on the selection of a set of representative products to meet food, mobility, housing, and other consumers' needs, environmental impacts of products are assessed over their full life cycle: from raw material extraction to production, distribution, use, and end-of-life phase. Life cycle inventories of representative products are multiplied by consumption statistics to assess the impact of an average European citizen in 2010 and 2015. Impacts are assessed considering the sixteen impact categories of the Environmental Footprint method. Results reveal that food is the most relevant area of consumption driving environmental impacts. Use phase is the most important life cycle stage for many impact categories, especially for the areas of consumption housing, mobility, and appliances. For the areas of consumption food and household goods, the most important life cycle phase is related to upstream processes, which corresponds to agricultural activities for food and manufacturing of products components for household goods. Apart from the results, the paper includes a detailed discussion on further methodological improvements and research needs to make use of the Consumer Footprint as an indicator for monitoring SDG 12 and for supporting sustainable production and consumption policies.

Environmental impacts of household consumption in Europe: Comparing process-based LCA and environmentally extended input-output analysis

The environmental impacts generated by household consumption are generally calculated through footprints, allocating the supply-chain impacts to the final consumers. This study compares the result of the Consumer Footprint indicator, aimed at assessing the impacts of household consumption in Europe, calculated with the two standard approaches usually implemented for footprint calculations: (i) a bottom-up approach, based on process-Life cycle assessment of a set of products and services representing household consumption, and (ii) a top-down approach, based on environmentally extended input-output tables (EXIOBASE 3). Environmental impacts are calculated considering 14 environmental impact categories out of the 16 included in the EF2017 impact assessment method. Both footprints show similar total values regarding climate change, freshwater eutrophication and fossil resource use, but in the meantime very large differences (more than a factor 2) regarding particulate matter, photochemical ozone formation, land use and mineral resource use. The exclusion of services in the bottom-up approach can explain only to some extent these differences. However, the two approaches converge in identifying food as the main driver of impact in most of the impact categories considered (with a generally lower contribution in top-down compared to bottom-up). Housing and mobility are relevant as well for some impact categories (e.g. particulate matter and fossil resource depletion). Some substances are identified as hotspot by both approaches, e.g. the emission of NH3 to air (for acidification and terrestrial eutrophication), of NOx to air (for acidification, marine and terrestrial eutrophication, and, to some extent, photochemical ozone formation), of P to water and to soil (for freshwater eutrophication) and of fossil CO2 to air (for climate change). Significant differences at the inventory side are key drivers for the differences in total impacts. These include: (i) differences in the intensity of emissions, (ii) differences in the coverage of elementary flows, (iii) differences in the level of detail relative to elementary flows. Overall, the key converging results from both approaches (in particular regarding most contributing areas of consumption and substances) can be considered as a robust basis to support the definition of policies aimed at reducing the environmental footprint of household consumption in Europe.

Extra Virgin Olive Oil and Cardiovascular Diseases: Benefits for Human Health

BACKGROUND AND OBJECTIVE

The cardioprotective properties of Mediterranean Diet were demonstrated for the first time from the Seven Country Study. In the last few decades, numerous epidemiological studies, as well as intervention trial, confirmed this observation, pointing out the close relationship between the Mediterranean diet and cardiovascular diseases. In this context, extra virgin olive oil (EVOO), the most representative component of this diet, seems to be relevant in lowering the incidence of cardiovascular events, including myocardial infarction and stroke. From a chemical point of view, 98-99% of the total weight of EVOO is represented by fatty acids, especially monounsaturated fatty acids such as oleic acid. Tocopherols, polyphenols and other minor constituents represent the remaining 1-2%. All these components may potentially contribute to "health maintenance" with their beneficial effects by EVOOO.

METHODS

Studies that examined the effect of EVOO supplementation in healthy subjects and in individuals at cardiovascular risk were included.

CONCLUSION

The studies analyzed demonstrated the role of EVOO as anti-inflammatory, antioxidant and vasodilatory nutrient that may contribute to lower the atherosclerotic burden.

Oleuropein, a component of extra virgin olive oil, lowers postprandial glycaemia in healthy subjects

AIMS

Extra virgin olive oil lowers postprandial glycaemia. We investigated if oleuropein, a component of extra virgin olive oil, exerts a similar effect on postprandial glycaemia and the underlying mechanism.

METHODS

Twenty healthy subjects were randomly allocated in a cross-over design to 20 mg oleuropein or placebo immediately before lunch. Postprandial glycaemia along with blood insulin, dipeptidyl-peptidase-4 (DPP-4) and glucagon-like peptide-1 and oxidative stress, which included soluble NADPH oxidase-derived peptide activity (sNox2-dp), 8-iso-prostaglandin-2α and platelet p47^phox phosphorylation, were analysed before and 2 h after meal.

RESULTS

After 2 h, subjects who assumed oleuropein had significantly lower blood glucose, DPP-4 activity and higher insulin and glucagon-like peptide-1 compared to placebo. Furthermore, sNox2-dp, 8-iso-PGF2α and platelet p47^phox phosphorylation were significantly lower in oleuropein- compared to placebo-treated subjects. DPP-4 significantly correlated with sNox2-dp [Spearman's rho (Rs) = 0.615; P < 0.001], p47^phox phosphorylation (Rs = 0.435; P < 0.05) and 8-iso- prostaglandin-2α (Rs = 0.33; P < 0.05). In vitro study demonstrated that hydroxytyrosol, a metabolite of oleuropein, significantly reduced p47^phox phosphorylation and isoprostane formation.

CONCLUSIONS

These findings indicate that oleuropein improves postprandial glycaemic profile via hampering Nox2-derived oxidative stress.

Glucocorticoids impair platelet thromboxane biosynthesis in community-acquired pneumonia

Previous reports suggest that community-acquired pneumonia (CAP) is associated with an enhanced risk of myocardial infarction (MI) and that enhanced platelet activation may play a role. Aims of this study were to investigate if urinary excretion of 11-dehydro-thromboxane (Tx) B₂, a reliable marker of platelet activation in vivo, was elevated in CAP and whether glucocorticoid administration reduced platelet activation. Three-hundred patients hospitalized for CAP were recruited and followed-up until discharge. Within the first 2 days from admission, urinary 11-dehydro-TxB₂ and serum levels of methylprednisolone and betamethasone were measured. 11-Dehydro-TxB₂ was also measured in a control group of 150 outpatients, matched for age, sex, and comorbidities. Finally, in-vitro studies were performed to assess if glucocorticoids affected platelet activation, at the same range of concentration found in the peripheral circulation of CAP patients treated with glucocorticoids. Compared to controls, CAP patients showed significantly higher levels of 11-dehydro-TxB₂ (110 [69-151] vs. 163 [130-225] pg/mg creatinine; p < 0.001). During the in-hospital stay, 31 patients experienced MI (10%). A COX regression analysis showed that 11-dehydro-TxB₂ independently predicted MI (p = .005). CAP patients treated with glucocorticoids showed significantly lower levels of 11-dehydro-TxB₂ compared to untreated ones (147 [120-201] vs. 176 [143-250] pg/mg creatinine; p < 0.001). In vitro, glucocorticoids-treated platelets showed a dose-dependent decrease of ADP-induced platelet aggregation, TxB₂ production, cPLA₂ phosphorylation and arachidonic acid release from the platelet membrane. In conclusion, platelet TxB₂ is overproduced in CAP patients and may be implicated in MI occurrence. Glucocorticoids reduce platelet release of TxB₂ in vitro and urinary excretion of 11-dehydro-TxB₂ in vivo and may be a novel tool to decrease platelet activation in this setting.

Prioritizing and optimizing sustainable measures for food waste prevention and management

Food waste has gained prominence in the European political debate thanks to the recent Circular Economy package. Currently the waste hierarchy, introduced by the Waste Framework Directive, has been the rule followed to prioritize food waste prevention and management measures according to the environmental criteria. But when considering other criteria along with the environmental one, such as the economic, other tools are needed for the prioritization and optimization. This paper addresses the situation in which a decision-maker has to design a food waste prevention programme considering the limited economic resources in order to achieve the highest environmental impact prevention along the whole food life cycle. A methodology using Life Cycle Assessment and mathematical programing is proposed and its capabilities are shown through a case study. Results show that the order established in the waste hierarchy is generally followed. The proposed methodology revealed to be especially helpful in identifying "quick wins" - measures that should be always prioritized since they avoid a high environmental impact at a low cost. Besides, in order to aggregate the environmental scores related to a variety of impact categories, different weighting sets were proposed. In general, results show that the relevance of the weighting set in the prioritization of the measures appears to be limited. Finally, the correlation between reducing food waste generation and reducing environmental impact along the Food Supply Chain has been studied. Results highlight that when planning food waste prevention strategies, it is important to set the targets at the level of environmental impact instead of setting the targets at the level of avoided food waste generation (in mass).

Systematic analysis of secondary life cycle inventories when modelling agricultural production: A case study for arable crops

Analysis of agricultural production with life cycle based methodologies is data demanding. To build comprehensive life cycle inventories, secondary datasets are commonly used when primary data are not available. However, different inventory data and modelling approaches are used to populate secondary datasets, leading to different results. The present study analyses the features of twelve secondary datasets to support datasets selection and proper interpretation of results. We assess twelve datasets for arable crop production in France, as modelled in three databases often used in the LCA field (Agri-footprint, ecoinvent and AGRIBALYSE). First, we compared system boundaries and general assumptions. Second, we focused on foreground systems comparing, inventory data, data sources and modelling approaches. Third, we performed a contribution analysis of impact assessment results to identify modelling choices that contribute most to differences in the results. Nine relevant elements were identified and assessed: definition of system boundaries and modelling of agricultural practices, characteristics of inventory data, agricultural operations, fertiliser application and fate, plant protection products application and fate, heavy metals inputs to the agricultural system and fate, irrigation assumptions, land use and transformation. The datasets differ greatly with respect to these elements. Hence, recommendations are drawn from the datasets comparison, supporting the selection of the datasets coherently with the goal and scope of a study and interpretation of results.

Beyond the throwaway society: A life cycle-based assessment of the environmental benefit of reuse

In the context of a circular economy, sustainable consumption is often seen as the antithesis of current consumption patterns, which have led to the definition of the so-called throwaway society. Reuse may provide a preferred alternative to other waste management options, because it promotes resource efficiency and may significantly reduce environmental impacts. To appraise the environmental benefits related to reuse of goods, a methodology adopting life cycle assessment (LCA) has been developed. A standardized procedure has been developed, identifying reference products within product category subject to reuse, and collecting reliable inventory data as a basis for calculating environmental impact through LCA. A case study on a second-hand shop is presented, and the avoided impacts are quantified. Inventory data were taken both from the literature and directly from sales and surveys submitted to customers. The results are presented, highlighting: 1) for each product category, the average avoided impacts for 1 unit of reused product considered; and 2) for the overall activities of the second-hand shop, the cumulative avoided impacts in 1 yr. In the case study, the higher contribution to avoided impacts comes from the apparel sector, due to the high amount of items sold, followed by the furniture sector, because of the high amount of environmental impacts avoided by the reuse of each single item.

The function of neuropilin/L1 complex

L1, a cell adhesion molecule of the Ig superfamily (IgCAM) plays a critical role in the formation of neuronal networks. This is reflected by the variety of clinical signs associated with the X-linked recessive neurological disorder that is caused by mutations in the L1 gene. L1 regulates the formation of axon fascicles and promotes neurite outgrowth through interaction with a wide spectrum of binding partners including cell adhesion molecules and extra-cellular matrix components. Here we describe the emerging evidence that indicates, in addition to these well-established functions, that L1 participates in the signaling of a secreted guidance cue of the Semaphorin family, Sema3A. Three types of experimental evidence support L1 as a key component of the Sema3A receptor complex. First, L1-deficient axons do not respond to Sema3A-induced chemorepulsion. Second, L1 and NRP1, the neuropilin responsible for Sema3A binding, associate through their extracellular domains, forming a cell surface heterocomplex. Third, a soluble form of L1 modulates axonal responsiveness to Sema3A, by converting Sema3A chemorepulsion into attraction.

Cis and trans interactions of L1 with neuropilin-1 control axonal responses to semaphorin 3A

Mutations in the L1 gene induce a spectrum of human neurological disorders due to abnormal development of several brain structures and fiber tracts. Among its binding partners, L1 immunoglobulin superfamily adhesion molecule (Ig CAM) associates with neuropilin-1 (NP-1) to form a semaphorin3A (Sema3A) receptor and soluble L1 converts Sema3A-induced axonal repulsion into attraction. Using L1 constructs containing missense pathological mutations, we show here that this reversion is initiated by a specific trans binding of L1 to NP-1, but not to L1 or other Ig CAMs, and leads to activation of the NO/cGMP pathway. We identified the L1-NP-1-binding site in a restricted sequence of L1 Ig domain 1, as a peptide derived from this region could reverse Sema3A repulsive effects. A pathological L1 missense mutation located in this sequence specifically disrupts both L1-NP-1 complex formation and Sema3A reversion, suggesting that the cross-talk between L1 and Sema3A might participate in human brain development.

Analysis of the L1-deficient mouse phenotype reveals cross-talk between Sema3A and L1 signaling pathways in axonal guidance

In humans, defects of the corticospinal tract have been attributed to mutations in the gene encoding L1 CAM, a phenotype that is reproduced in L1-deficient mice. Using coculture assays, we report that Sema3A secreted from the ventral spinal cord repels cortical axons from wild-type but not from L1-deficient mice. L1 and neuropilin-1 (NP-1) form a stable complex, and their extracellular domains can directly associate. Thus, L1 is a component of the Sema3A receptor complex, and L1 mutations may disrupt Sema3A signaling in the growth cone, leading to guidance errors. Addition of soluble L1Fc chimeric molecules does not restore Sema3A responsiveness of L1-deficient axons; instead, it converts the repulsion of wild-type axons into an attraction, further supporting a function for L1 in the Sema3A transducing pathways within the growth cone.

The RR Lyrae Star U Comae as a Test for Nonlinear Pulsation Models

We use high-precision multiband photometric data of the first-overtone RR Lyrae star U Comae to investigate the predictive capability of full-amplitude, nonlinear, convective hydrodynamical models. The main outcome of this investigation is that theoretical predictions properly account for the luminosity variations along a full pulsation cycle. Moreover, we find that this approach, because of the strong dependence of this observable and of the pulsation period on stellar parameters, supplies tight constraints on stellar mass, effective temperature, and distance modulus. Pulsational estimates of these parameters appear in good agreement with empirical ones. Finally, a well-defined bump just before the luminosity maximum gave the unique opportunity to calibrate the turbulent convection model adopted for handling the coupling between pulsation and convection.

Opposing roles for neurotrophin-3 in targeting and collateral formation of distinct sets of developing cortical neurons

Neurotrophin-3 and its receptor TrkC are expressed during the development of the mammalian cerebral cortex. To examine whether neurotrophin-3 might play a role in the elaboration of layer-specific cortical circuits, slices of layer 6 and layers 2/3 neurons were cultured in the presence of exogenously applied neurotrophin-3. Results indicate that neurotrophin-3 promotes axonal branching of layer 6 axons, which target neurotrophin-3-expressing layers in vivo, and that it inhibits branching of layers 2/3 axons, which avoid neurotrophin-3-expressing layers. Such opposing effects of neurotrophin-3 on axonal branching were also observed with embryonic cortical neurons, indicating that the response to neurotrophin-3 is specified at early developmental stages, prior to cell migration. In addition to its effects on fiber branching, axonal guidance assays also indicate that neurotrophin-3 is an attractive signal for layer 6 axons and a repellent guidance cue for layers 2/3 axons. Experiments with specific antibodies to neutralize neurotrophin-3 in cortical membranes revealed that endogenous levels of neurotrophin-3 are sufficient to regulate branching and targeting of cortical axons. These opposing effects of neurotrophin-3 on specific populations of axons demonstrate that it could serve as one of the signals for the elaboration of local cortical circuits.

Dual action of a ligand for Eph receptor tyrosine kinases on specific populations of axons during the development of cortical circuits

The structural basis of cortical columns are radially oriented axon collaterals that form precise connections between distinct cortical layers. During development, these connections are highly specified from the initial outgrowth of collateral branches. Our previous work provided evidence for positional cues confined to individual layers that induce and/or prevent the formation of axon collaterals in specific populations of cortical neurons. Here we demonstrated with in situ hybridization techniques that mRNA of the Eph receptor tyrosine kinase EphA5 and one of its ligands, ephrin-A5, are present in distinct cortical layers, at a time when intrinsic connections are being formed in the cortex. Axonal guidance assays indicate that ephrin-A5 is a repellent signal for a populations of axons that in vivo avoid the cortical layer expressing ephrin-A5. In contrast to its established role as a repulsive axonal guidance signal, ephrin-A5 specifically mediates sprouting of those cortical axons that target the ephrin-A5-expressing layer in vivo. These results identify a novel function of ephrin-A5 on axonal arbor formation. The laminar distribution and the dual action on specific populations of axons suggest that ephrin-A5 plays a role in the assembly of local cortical circuits.

How do wiring molecules specify cortical connections?

The laminar and columnar organization of the cortex is reflected in the projections to and from the cortex and in the intracortical connections. During development of the cerebral cortex, growing axons are able to distinguish between the different cortical layers, and cortical axons originating from different laminae respond to different layer-specific signals. Here we consider some experimental systems for identifying mechanisms that contribute to the elaboration of layer-specific cortical connections.

Membrane-associated molecules regulate the formation of layer-specific cortical circuits

The columnar organization of the mammalian neocortex is based on radially oriented axon collaterals which precisely link cells from distinct cortical layers. During development, these interlaminar connections are specific from their initial outgrowth: collaterals form only in the target layers and there are no transient axonal collaterals in the nontarget layers. To examine whether positional cues within individual cortical layers regulate the laminar specificity of collateral formation, explants of cells destined for different cortical layers were cultured on membranes prepared from target and nontarget layers. Axonal growth and branching were examined on homogeneous membrane substrates and on alternating stripes of membranes from different layers. Results show that axons branch preferentially on membrane substrates from those layers that they would target in vivo. In addition, when cortical axons were given a choice to grow on membranes from either their target or their nontarget layer, they exhibited a clear preference for the target layers. This indicates that membrane-associated cues confined to individual layers regulate the formation of collaterals of cortical axons and restrict their growth to their target layers. Heat inactivation of membranes from target layers resulted in reduced axonal branching. The same manipulation of membranes from nontarget layers increased axonal branching for one population of cortical neurons. Taken together, these results suggest that membrane-associated molecules confined to individual layers induce and prevent the formation of axon collaterals in distinct populations of cortical neurons. Thus, the expression of layer-specific cues provides important constraints for the remodeling of local circuits during cortical development.

Developmental strategies underlying the elaboration of cortical circuits

The mammalian cerebral cortex is organized in layers and columns, which are reflected in the local intrinsic connections and in the projections to and from the cortex. It is well established that the development of the columnar architecture is under the influence of neuronal activity, but little is known about the mechanisms that control the laminar specificity of cortical circuits. Here we review some recent studies which show that diffusible and membrane-associated molecules provide sufficient information to reconstruct layer-specific intrinsic and extrinsic cortical circuits under in vitro conditions.

Specification of layer-specific connections in the developing cortex

One of the basic tasks of neurobiology is to understand how the precision and specificity of neuronal connections is achieved during development. In this paper we reviewed some recent in vitro studies on the developing mammalian cerebral cortex that have been made towards this end. The results of these experiments provided evidence that membrane-associated molecules are instrumental for the formation of specific afferent and efferent cortical projections. Substrate-bound molecules guide growing axons towards their target, regulate the timing of thalamocortical innervation and mediate target cell recognition. Moreover, a newly described glycoprotein, defined by a monoclonal antibody, revealed a molecular heterogeneity in the developing white matter. Since this molecule has opposite effects on thalamic and cortical axons, it might play a role in the segregation of axons running to and from the cortex. Substrate-bound cues are important during the formation of local cortical circuits. In vitro assays demonstrated that molecular components confined to individual cortical layers control the laminar specificity of cortical axon branching. This suggests that similar developmental strategies contribute to the laminar specification of extrinsic and intrinsic cortical circuits. Thus substrate-bound molecules might provide the framework for subsequent activity-dependent mechanisms that control the elaboration of precise connections between the cortical columns. A major challenge ahead is to identify the factors that mediate these processes and to determine their mode of action. Recently, two families of proteins, the netrins and the semaphorins/collapsins, have been identified as growth cone signals in the developing spinal cord (reviewed in Goodman, 1994; Colamarino and Tessier-Lavigne, 1995a; Dodd and Schuchardt, 1995; Kennedy and Tessier-Lavigne, 1995). Semaphorins/collapsins appear to regulate axonal guidance by repelling growth cones and by inhibiting axonal branching and synapse formation. Originally, netrins have been purified as diffusible chemoattractants for commissural axons of the dorsal spinal cord, but it is now well established that they can also function as chemorepellent factors for other classes of neurons. Since netrins are related to extracellular matrix components and since they can bind to the cell surface, they might also act as local guidance cues. A possible role of netrins and semaphorins/collapsins in the development of cortical connections is likely to be resolved in the near future. The identification of the factors that regulate specific branching patterns of cortical neurons might provide a better understanding of cortical development, but it might also be relevant to some aspects of plasticity and repair in the adult cortex.

Comparison of ST segment changes on standard and Holter electrocardiogram during exercise testing

In order to compare the ST segment changes recorded simultaneously on Holter (Del Mar Avionics 445B recorder and DCG VII Scanner) and standard electrocardiogram, 22 patients with chest discomfort and normal resting ECG were evaluated during exercise testing. The conventional ECG was recorded using chest lead V5 and a modified lead II. The Holter recording was done using the bipolar chest lead CM5 and the same modified lead II. Bifurcating electrodes permitted simultaneous recording of electrocardiogram on both systems from the same electrode sites. Seven of the 22 patients had a positive test and 15 had a negative test by both systems. In 7 positive cases the amplitude of ST segment depression was compared. The Holter lead CM5 showed higher amplitude of ST segment depressions in 6 cases compared to the conventional lead V5: 3 cases by 0.5 mm; 2 cases by 1 mm and 1 case by 2.5 mm. In 1 case it was identical. The amplitude of ST segment depression in lead CM5 ranged from 1 to 3.5 mm (mean 2.2 +/- 0.6 mm) and in lead V5 from 1 to 2.5 mm (mean 1.5 +/- 0.6 mm). Thus the amplitude of ST depression was higher in lead CM5 by a mean of 0.7 mm compared to the lead V5. ST segment depression was present only in 6 cases in the modified lead II. ST segment depressions were reproduced faithfully in 3 patients and within the variation of 0.5 mm in other 3 cases by the Holter system.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegalic cardiomyopathy. An echocardiographic study

Eighteen acromegalic patients (A) and 18 controls without clinical evidence of cardiac involvement and/or endocrine disease (C), matched for sex, age, body surface area, and blood pressure (BP), were investigated by M-mode (2-D derived) echocardiography, to clarify the prevalence and the possible determinants of left ventricular hypertrophy (LVH). Seven patients in each group were hypertensive (BP greater than 160/95 mmHg). Left ventricular mass (LVM) was 183.1 +/- 60.0 g/m2 in A and 130 +/- 25.9 g/m2 in C. A LVM above 140 g/m2 (that is the upper normal range in our laboratory) was found in 15/18 A and 2/18 C. The LVH was concentric (h/r greater than 0.45) in 12/15 A and 1/2 C. Systolic function indexes (% FS, end-systolic stress/end-systolic volume), cardiac index and total peripheral resistance index (as determined by echo) were within the normal range and similar in both groups. No correlation was found between LVM and BP, LVM and GH plasma levels, LVM and Sm-C levels. A significant correlation was found between LVM and duration of the disease (r 0.44; p less than 0.05). Our data confirm that LVH is an early and frequent finding in acromegaly. Its prevalence is not entirely accounted for by such factors as body size, BP or increased cardiac output. Metabolic factors may play a major role, and a long lasting exposition to increased GH levels seems the most relevant determinant of LVH.

Prevalence of atherosclerotic involvement of the internal carotid artery in hypertensive patients

The prevalence of atherosclerotic involvement of the internal carotid arteries, as diagnosed through an echo-Doppler imaging system with pulsed Doppler spectral analysis was evaluated in 49 hypertensives who had a negative history for neurological symptoms and 49 matched controls. The prevalence was 24.5% in the hypertensive group and 10.2% in the controls with a statistically significant difference (chi-square = 6.07, P less than 0.01). Two hypertensives had severe stenosis (above 50% diameter reduction) and 7 had potentially embolic lesions (irregular surface, inhomogeneous appearance). No one of the matched controls was as severely involved. We conclude that arterial hypertension can account for enhanced prevalence of carotid artery disease in asymptomatic patients.

Hemispheric TIA and amaurosis fugax: what is their relation to stenotic lesions of internal carotid artery?

We evaluated the correlation of clinical and echo-Doppler findings from the internal carotid artery (ICA) in 17 patients with amaurosis fugax (AF) and in 68 patients with hemispheric TIA (H-TIA). In the study population as a whole, moderate stenoses (20%-49% diameter reduction) were the most prevalent finding in the symptomatic ICA, being detectable in 51.6% of cases. Total occlusions were found in an unexpectedly high percentage (7.5%). Asymptomatic ICAs, that were contralateral to the symptoms, showed the same degree of atherosclerotic involvement as the symptomatic ICAs. When we compared AF with H-TIA, we found a significantly higher prevalence of severe hemodynamically significant stenoses in the former (52.6% vs. 18.8%, chi-square test 10.85, P less than 0.05). Thus, we conclude that in the vast majority of patients with transient neurological symptoms a bilateral ICA involvement is to be expected. The side on which the symptoms occur does not indicate which ICA is more severely stenotic except in AF, where a severe involvement of the ipsilateral ICA is most likely.

[Prevalence, characteristics and clinical correlates of left ventricular hypertrophy in stable hypertension. Echocardiographic study]

251 in stable hypertensives were studied with M-Mode and two-dimensional echocardiography, in order to evaluate the prevalence of left ventricular hypertrophy (LVH), its patterns and clinical correlates. 54 subjects (21%) had been treated previously with antihypertensive drugs while the remaining 197 (79%) had not. A normal left ventricle was found in 69 subjects (27.1%; group A); a concentric LVH (h/r greater than or equal to 0.45) was found in 99 (39.4%; group B), while an eccentric LVH (left ventricular myocardial mass index greater than 140 g/m2, h/r less than 0.45) in 83 (43.1%; group C). An asymmetric LVH (septum to posterior wall thickness ratio greater than or equal to 1.3) was found in 33 subjects (3 did not fulfill the criteria for LVH, 21 had a concentric, and 10 an eccentric LVH). Mean age was significantly higher in group B as compared to groups A and C. The body mass index was comparable in all groups. Mean systolic blood pressure was significantly higher in groups B and C as compared to A. The duration and the severity of hypertension did not differ among the three groups. W.H.O. stage III was absent in group A, but no differences were found between group B and C as for W.H.O. stage distribution. We conclude that such factors as BMI, duration and severity of hypertension poorly correlate with the occurrence of LVH and its patterns. The fact that group B hypertensives were older than the others on average is against the hypothesis that eccentric hypertrophy follows the concentric pattern. Whether these two patterns represent separate entities in relation to different hemodynamic profiles deserves further investigation.

Prospective evaluation of combined carotid and coronary surgery

In order to evaluate the effectiveness of combined carotid and coronary surgery in reducing the incidence of neurological disturbances after coronary artery bypass grafting (CABG), 144 consecutive candidates for CABG (group I) were screened for carotid disease noninvasively with Doppler ultrasonography (duplex). Twenty-six (18%) were considered at risk for stroke because of a severe (above 50% diameter reduction) stenosis; 20 (4 symptomatic and 16 asymptomatic) underwent combined surgery. Forty-seven other patients (group II) underwent CABG surgery without previous Doppler investigation. Only three patients (1.5% of the survivors) developed transient neurological disturbances after surgery; two who had normal internal carotid arteries belonged to group I, and one to group II. None of the six patients at risk for stroke who underwent only CABG developed neurological symptoms. The incidence of intra- and postoperative cardiac complications of the group who had CABG only compared to that of the group with combined surgery. We conclude that, although safe, combined surgery is not to be performed systematically on candidates for CABG with a significant internal carotid artery stenosis.