Plasma biomarkers for Alzheimer's disease: a field-test in a memory clinic

BACKGROUND

The key Alzheimer's disease (AD) biomarkers are traditionally measured with techniques/exams that are either expensive (amyloid-positron emission tomography (PET) and tau-PET), invasive (cerebrospinal fluid Aβ₄₂ and p-tau₁₈₁), or poorly specific (atrophy on MRI and hypometabolism on fluorodeoxyglucose-PET). Recently developed plasma biomarkers could significantly enhance the efficiency of the diagnostic pathway in memory clinics and improve patient care. This study aimed to: (1) confirm the correlations between plasma and traditional AD biomarkers, (2) assess the diagnostic accuracy of plasma biomarkers as compared with traditional biomarkers, and (3) estimate the proportion of traditional exams potentially saved thanks to the use of plasma biomarkers.

METHODS

Participants were 200 patients with plasma biomarkers and at least one traditional biomarker collected within 12 months.

RESULTS

Overall, plasma biomarkers significantly correlated with biomarkers assessed through traditional techniques: up to r=0.50 (p<0.001) among amyloid, r=0.43 (p=0.002) among tau, and r=-0.23 (p=0.001) among neurodegeneration biomarkers. Moreover, plasma biomarkers showed high accuracy in discriminating the biomarker status (normal or abnormal) determined by using traditional biomarkers: up to area under the curve (AUC)=0.87 for amyloid, AUC=0.82 for tau, and AUC=0.63 for neurodegeneration status. The use of plasma as a gateway to traditional biomarkers using cohort-specific thresholds (with 95% sensitivity and 95% specificity) could save up to 49% of amyloid, 38% of tau, and 16% of neurodegeneration biomarkers.

CONCLUSION

The implementation of plasma biomarkers could save a remarkable proportion of more expensive traditional exams, making the diagnostic workup more cost-effective and improving patient care.

Autoantibodies directed against apolipoprotein A-1 as a potential contributor to non-alcoholic fatty liver disease

Background

Non-Alcoholic Fatty Liver Disease (NAFLD) represents an increasing cause of liver disease worldwide. Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in these patients. Although NAFLD pathophysiology is not fully understood alterations in fat metabolism seem to play a role. Autoantibodies against apolipoprotein A-1 (anti-apoA-1 IgG) are a novel cardiovascular risk factor to which have been recently attributed a metabolic role in addition to a well-established macrophage-mediated inflammatory effect and have a function as a disruptor of the cholesterol pathway.

Purpose

This study aims at evaluating a possible role of anti-apoA-1 IgG in NAFLD.

Methods

Serum from 137 NAFLD patients were tested for anti-apoA-1 IgG prevalence. In vitro, SREBP1, SREBP2 expressions were assessed in the human hepatic cell line HepaRG by western blot analysis and bodipy staining was used to evaluate the lipid droplet content. Mescoscale technology platform was used to measure TNF-α, IL-6 and IL-8 cytokines/chemokines in HepaRG supernatants. Oil Red O staining was used to detect lipid accumulation in liver sections from ApoE−/− mice.

Results

Elevated anti-apoA-1 IgG seropositivity was found in patients with NAFLD (46%). In vitro, anti-apoA-1 IgG and not control IgG induced lipid accumulation in hepatic cells (5.9 vs 2.5, P=0.0008) and this lipid overload was associated with a high SREBP1 but not SREBP2 expression. Furthermore, anti-apoA-1 IgG and not control antibodies caused a significant large increase of the proinflammatory cytokines IL-6 (680 vs. 163 pg/mL, P=0.03) and TNF-α (391 vs 266 pg/mL, P=0.04) as well as of the chemokine IL-8 (174.1 vs. 72.6 ng/mL, P=0.03) detected in the hepatic cell supernatants. In vivo, anti-apoA-1 IgG and not control IgG also induced higher lipid accumulation in the livers of ApoE−/− mice (1.23 vs 0.53, P=0.03).

Conclusion

Anti-apoA-1 IgG are frequent in NAFLD, cause a strong inflammatory response and promote lipid accumulation through SREBP1 activation in human hepatic cells. We hypothesize that anti-apoA1 IgG may be a potential contributor in the development of NAFLD.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Geneva University Hospital

HIV-infected patients display increased proatherogenic anti-apolipoprotein A1 autoantibodies, inflammatory and metabolomic markers

Background

HIV-infected patients display an increased risk of cardiovascular events. HIV and antiretroviral therapy (ART) have both been suggested to increase this risk but their specific role remains unclear. Autoantibodies against apolipoprotein A1 (anti-apoA1 IgG) are also associated with cardiovascular risk. The aim of this study was to analyse anti-apoA1 IgG levels and inflammatory markers as well as the metabolomic profile in a cohort of HIV-free, ART-experienced and naïve HIV-infected patients.

Methods

144 participants from a South African cohort were categorised into HIV-free (n=50), HIV-infected/ART-experienced (n=50) and HIV-infected/ART-naïve (n=44) groups. The levels of anti-apoA1 IgG were assessed by homemade ELISA assays. We performed targeted metabolomic analyses using standard operating procedures and measured inflammatory biomarkers using the Meso Scale Discovery® platform. Additionally, we conducted in vitro experiments on human aortic endothelial cells treated with anti-apoA1 IgG and assessed levels of adhesion molecules.

Results

Inflammatory markers (IFNg, IL-6, IL-10, TNFa, CRP all p&lt;0.05), circulating adhesion molecules (ICAM-1 and VCAM-1, p&lt;0.05), anti-apoA1 IgG levels were increased in HIV-infected patients compared to HIV-free participants.

While ART treatment significantly reduced IFNg, IL-10, TNFa, VCAM-1, anti-apoA1 IgG levels, no significant differences were observed in other biomarkers between ART-experienced and naïve participants. Treatment of human aortic endothelial cells with anti-apoA1 IgG (40μg/ml) induced a significant increase in these adhesion molecules compared to cells treated with control IgG (40μg/ml). Metabolomic analyses identified 257 endogenous circulating metabolites in plasma. Among these metabolites, we found that in HIV-free and infected patients 14 and 17 metabolites were significantly correlated with anti-apoA1 IgG levels, respectively. Among these 17 metabolites, 2 were positively correlated with the tryptophan pathway; kynurenine (r=0.292, p=0.0069) and 5-hydroxyindolacetate (r=0.316, p=0.0019). Interestingly, kynurenine was not significantly correlated with anti-apoA1 IgG levels in HIV-free patients.

Conclusion

HIV-infected patients displayed a more proatherogenic profile compared to HIV-free subjects. Anti-apoA1 IgG induced adhesion molecules expression. Metabolomics identified metabolites that were significantly associated with anti-apoA1 IgG levels and inflammatory biomarkers known to underlie atherosclerosis burden.

Funding Acknowledgement

Type of funding sources: None.

Liver stiffness change with HCV cure in HIV-infected patients on non-nucleoside analogues

BACKGROUND

Liver stiffness (LS) at sustained viral response (SVR) is strongly associated with a lower incidence of subsequent hepatic events. HIV NNRTIs may have a beneficial impact on fibrogenesis.

OBJECTIVES

Our aim was to analyse the influence of NNRTI-based therapy on the change in LS from starting direct-acting antiviral (DAA) therapy to achieving SVR in HIV/HCV-coinfected patients.

METHODS

Three hundred and thirteen HIV/HCV-coinfected patients who fulfilled the following criteria were included: (i) had achieved SVR with an IFN-free, DAA-including regimen; (ii) LS ≥9.5 kPa before therapy; (iii) LS measurement available at SVR; (iv) seronegative for HBsAg; and (v) ART containing 2 NRTIs plus either 1 NNRTI or 1 integrase inhibitor (INI) or 1-2 NRTIs plus 1 PI. LS changes were assessed.

RESULTS

Seventy-four patients received NNRTI-based combinations [53 (71.6%) rilpivirine and 16 (21.6%) efavirenz] and 239 patients received other regimens. At baseline, the median (IQR) LS was 16.7 kPa (11.8-25.6) in the NNRTI group and 17.3 kPa (11.9-27.4) in the non-NNRTI group (P = 0.278). The median (IQR) percentage of LS decrease from baseline to SVR was 35.2% (18.2%-52.3%) for NNRTI-based therapy and 29.5% (10%-45.9%) for PI- or INI-based therapy (P = 0.018). In multivariate analysis, adjusted for sex, age, HCV genotype, NRTI backbone and propensity score for HIV therapy, NNRTI-based regimen use was associated with a higher LS decrease [β = 11.088 (95% CI = 1.67-20.51); P = 0.021].

CONCLUSIONS

Treatment with NNRTI plus 2 NRTI combinations is associated with a higher LS decline than other ART combinations in HIV/HCV-coinfected patients receiving DAA-based therapy.

Auto-antibodies against apolipoprotein A-1 block cancer cells proliferation and induce apoptosis

Auto-antibodies against apoA-1 (anti-apoA-1 IgGs) have been identified as important actors of atherosclerosis development through pro-inflammatory and pro-atherogenic properties and to also induce apoptosis in tumoral neuronal and lymphocyte derived cell lines through unknown mechanisms. The purpose of this study was to explore the cellular pathways involved in tumoral cell survival modulated by anti-apoA-1 antibodies. We observed that anti-apoA-1 antibodies induce growth arrest (in G2/M phase) and cell apoptosis through caspase 3 activation, accompanied by a selective p53 phosphorylation on serine 15. RNA sequencing indicated that anti-apoA-1 IgGs affect the expression of more than 950 genes belonging to five major groups of genes and respectively involved in i) cell proliferation inhibition, ii) p53 stabilisation and regulation, iii) apoptosis regulation, iv) inflammation regulation, and v) oxidative stress. In conclusion, anti-apoA-1 antibodies seem to have a role in blocking tumoral cell proliferation and survival, by activating a major tumor suppressor protein and by modulating the inflammatory and oxidative stress response. Further investigations are needed to explore a possible anti-cancer therapeutic approach of these antibodies in very specific and circumscribed conditions.

Evaluation of antiretroviral therapy on metabolomics and atherogenic markers in HIV patients

Background

HIV-infected patients display an increased risk of cardiovascular events. HIV and antiretroviral therapy (ART) have both been suggested to increase the risk of cardiovascular events but their specific role remains unclear.

Purpose

The aim of this study was to analyse the metabolomic profile in a cohort of HIV-free, ART experienced and naïve HIV-infected patients and to identify the metabolite associated with atherosclerosis development and endothelial dysfunction. The impact of ART on inflammatory and autoimmune biomarkers known to underlie atherosclerosis burden was also investigated.

Methods

144 participants from a South African cohort were divided in three groups: HIV-free (n=50), HIV-infected/ART experienced (n=50) and HIV-infected/ART naïve (n=44). Targeted metabolomic analyses were performed using standard operating procedures. Atherosclerosis development was evaluated using coronary intima-media thickness (CITM) and endothelial dysfunction by flow-mediated dilation (FMD). Inflammatory biomarkers were measured with the Meso Scale Discovery® platform. The levels of autoantibodies against apolipoprotein A1 (anti-apoA1 IgG) and its specific C-terminal domain (anti-F3L1) levels were assessed by homemade ELISA assays.

Results

257 endogenous metabolites were identified in the 144 samples. Regarding the association of metabolites with the vascular markers, eight metabolites were found to be associated with FMD and eleven with CIMT. Among these metabolites, cytosine was negatively correlated with FMD (r=−0.22, p=0.009), while positively with CIMT (r=0.20, p=0.026). Interestingly, from the list of these 18 metabolites, ART-experienced patients displayed an increase in kynurenine (p=0.0007) and 3–2-hydroxyphenyl-propanoate (p=0.0009) levels and a decrease in itaconate (p=0.021) levels compared to ART-naïve patients. HIV-infected patients displayed a more proatherogenic profile compared to HIV-free subjects. Inflammatory markers (IFNg, IL-6, IL-10, TNFα, CRP all p&lt;0.05), circulating adhesion molecules (ICAM-1 and VCAM-1, p&lt;0.05), anti-apoA1 IgG and anti-F3L1 (p&lt;0.05) and CIMT (p=0.05) were increased while FMD (p=0.054) was decreased in HIV-infected patients compared to HIV-free participants. While ART treatment significantly reduced IFNg, IL-10, TNFα, VCAM-1, anti-apoA1 IgG and anti-F3L1, no significant differences were observed in other biomarkers between ART-experienced and naïve participants.

Conclusion

Metabolomic analysis identified metabolites that were differentially expressed in the 3 groups. 18 metabolites were significantly correlated with FMD or CITM, among which the levels of kynurenine, 3–2-hydroxyphenyl-propanoate and itaconate were modulated by ART. HIV patients displayed increased levels of inflammatory markers, circulating adhesion molecules and anti-apoA1 IgG which was downregulated by ART.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Fondation De Reuter; Fondation Schmidheiny; Fondation Prévot; SwissLife AG; Fondation pour la lutte pour le cancer et la recherche bio-médicale

P5343The presence of anti-apolipoprotein A1 autoantibodies is associated with a pro-atherogenic profile in HIV-infected patients

Background

With the access to antiretroviral therapy (ART), the mortality related to the human immunodeficiency virus (HIV) has dropped, shifting the clinical challenges towards chronic disease management, including cardiovascular disease (CVD) risk assessment. Factors that potentially contribute to the physiopathology of HIV-related CVD include the HI-virus itself, adverse effects of ART, and processes such as dyslipidemia, inflammation, immune/autoimmune activation and endothelial injury. Among autoantibodies of possible cardiovascular relevance, those directed against apolipoprotein A-1 (anti-apoA-1 IgG) were shown to predict major adverse cardiovascular events and promote atherogenesis.

Purpose

The aim of the study was to evaluate the prevalence of anti-apoA1 IgG in HIV-free and ART experienced and naïve HIV-infected patients as well as the association between anti-apoA1 IgG levels and, indices of viral suppression, clinical parameters (10 year Framingham Risk Score (FRS)) and inflammatory biomarkers, known to underlie atherosclerosis burden in these patients.

Methods

Anti-apoA1 IgG serum levels were assessed by a homemade ELISA assay in 144 participants from a South African cohort divided in three groups: HIV-free (n=50), HIV-infected/ART experienced (n=50) and HIV-infected/ART naïve (n=44). Inflammatory biomarkers were measured.

Results

HIV-infected patients displayed an increased pro-atherogenic biomarker profile compared to HIV-free subjects, but not difference in the FRS was observed between these two groups. Regarding anti-apoA1 IgG, 24% of HIV-free patients tested positive compared to 40% and 70% in HIV-infected/ART experienced and naïve groups, respectively. HIV-infected, anti-apoA1 IgG positive patients showed a significant decrease in CD4+ counts (p=0.003) and a significant increase in viremia (p=0.0130), mean heart rate (p=0.0243), albuminuria (p=0.0155), pro-inflammatory biomarkers (IFNγ, IL-10, TNFα, MIPα; all p<0.05), circulating levels of intercellular adhesion molecule (ICAM-1) (p=0.0217) and vascular cell adhesion molecule (VCAM-1) (p=0.003) compared to anti-apoA1 IgG negative ones. Of note, while this profile was maintained in HIV-infected/ART experienced, these significant differences were lost in HIV-infected/ART naïve patients. No significant difference in FRS was observed between anti-apoA1 IgG positive vs negative individuals in all groups.

Conclusions

HIV-infected patients presented with an increased prevalence of anti-apoA1 IgG compared to HIV-free subjects. In HIV-infected/ART experienced patients, anti-apoA1 IgG levels were associated with low CD4+ counts, levels of adhesion molecules and pro-inflammatory responses, features associated with increased cardiovascular events. ART highlighted pro-atherogenic differences between HIV-infected anti-apoA1 IgG negative and positive patients.

Separation of blood microsamples by exploiting sedimentation at the microscale

Microsample analysis is highly beneficial in blood-based testing where cutting-edge bioanalytical technologies enable the analysis of volumes down to a few tens of microliters. Despite the availability of analytical methods, the difficulty in obtaining high-quality and standardized microsamples at the point of collection remains a major limitation of the process. Here, we detail and model a blood separation principle which exploits discrete viscosity differences caused by blood particle sedimentation in a laminar flow. Based on this phenomenon, we developed a portable capillary-driven microfluidic device that separates blood microsamples collected from finger-pricks and delivers 2 µL of metered serum for bench-top analysis. Flow cytometric analysis demonstrated the high purity of generated microsamples. Proteomic and metabolomic analyses of the microsamples of 283 proteins and 1351 metabolite features was consistent with samples generated via a conventional centrifugation method. These results were confirmed by a clinical study scrutinising 8 blood markers in obese patients.

Detection of hepatitis E virus RNA in saliva for diagnosis of acute infection

Diagnosis of acute hepatitis E virus (HEV) infection is established by detection of anti-HEV IgM antibodies by ELISA or by amplification of serum viral RNA. Here, we evaluate the diagnostic value of testing HEV RNA in saliva to identify patients with acute HEV infection. Prospective proof-of-concept study including patients with acute hepatitis. Whole blood and neat saliva samples were obtained from all patients. Saliva samples were processed and analysed for HEV RNA by RT-PCR within 2 hr after collection. A total of 34 patients with acute hepatitis and 12 healthy donors were included in the study. HEV RNA in serum was confirmed by RT-PCR in eight of these patients (23.5%; 95% CI: 12.2%-40.2%). HEV was isolated in the saliva of eight of 34 patients (23.5%; 95% CI: 12.2%-40.2%). All patients with HEV RNA amplified in saliva had detectable HEV RNA in serum. HEV was isolated neither in the saliva of any of the 26 patients without detectable HEV RNA in serum nor in healthy donors. Our study suggests that acute HEV infection could be diagnosed by assessing viral load in saliva.

Familial Hepatitis E Outbreak Linked to Wild Boar Meat Consumption

An HIV-infected patient was diagnosed with acute hepatitis E infection in our hospital. An epidemiological inquiry was performed to collect demographic, food and animal exposure variables in order to identify the potential route of transmission. The patient reported that his family traditionally hunted wild boar for food. All family members were analysed for hepatitis E virus infection. Additionally, route of transmission by wild boar meat consumption and prevalence of HEV infection among wild boar from the same hunting area were investigated. In all-family members (n = 8), HEV-RNA was amplified. Two wild boar meat slices consumed was analysed, showing the presence of HEV. The virus isolated was consistent with genotype 3, revealing 100% homology between family members and meat. Additionally, we tested nine wild boar hunted in the same hunting area. All of them were RNA-HEV positive, isolating the same HEV genotype 3 viral strain. We demonstrated by phylogenetic analysis zoonotic transmission of HEV by wild boar meat consumption. The prevalence of HEV infection among wild boar found in our study suggests that this species is an important route of transmission to human.

Rural habitat as risk factor for hepatitis E virus seroconversion in HIV-infected patients: A prospective longitudinal study

Our objective was to determine the incidence and clinical manifestations of acute hepatitis E virus (HEV) in HIV-infected patients. A prospective longitudinal study including HIV-infected HEV-seronegative patients was conducted; HEV seroconversion (to IgG and/or IgM) was the main outcome variable. All patients were tested for HEV antibodies every 3-6 months. For patients who developed HEV seroconversion, a data collection protocol was followed to identify associated clinical manifestations and analytical alterations. A total of 627 patients (89.9%) were followed during a median of 11.96 months (IQR: 8.52-14.52 months) and formed the study population. Forty-one patients developed detectable anti-HEV antibodies (7.2 cases per 100 patients/year). Our study found a high incidence of HEV in HIV-infected patients in southern Spain strongly associated with a rural habitat.

Association between ethnicity and obesity with high-density lipoprotein (HDL) function and subclass distribution

BACKGROUND

Obesity and low high-density lipoprotein-cholesterol (HDL-C) levels are associated with cardiovascular risk. Surprisingly, despite a greater prevalence of obesity and lower HDL concentrations than white women, black South African women are relatively protected against ischaemic heart disease.

METHODS

We investigated whether this apparent discrepancy may be related to different HDL function and subclass distribution in black and white, normal-weight and obese South African women (n = 40). HDL functionality was assessed by measuring paraoxonase (PON) activity, platelet activating factor acetylhydrolase (PAF-AH) activity, Oxygen Radical Absorbance Capacity (ORAC) and quantification of the expression of vascular cell adhesion molecule in endothelial cells. PON-1 and PAF-AH expression was determined in isolated HDL and serum using Western blotting. Levels of large, intermediate and small HDL subclasses were measured using the Lipoprint® system.

RESULTS

PON activity was lower in white compared to black women (0.49 ± 0.09 U/L vs 0.78 ± 0.10 U/L, p < 0.05), regardless of PON-1 protein levels. Obese black women had lower PAF-AH activity (9.34 ± 1.15 U/L vs 13.89 ± 1.21 U/L, p <0.05) and HDL-associated PAF-AH expression compared to obese white women. Compared to normal-weight women, obese women had lower large HDL, greater intermediate and small HDL; an effect that was more pronounced in white women than black women. There were no differences in antioxidant capacity or anti-inflammatory function across groups.

CONCLUSIONS

Our data show that both obesity and ethnicity are associated with differences in HDL functionality, while obesity was associated with decreases in large HDL subclass distribution. Measuring HDL functionality and subclass may, therefore, be important factors to consider when assessing cardiovascular risk.

KIR2DS2 as predictor of thrombocytopenia secondary to pegylated interferon-alpha therapy

Our aim was to evaluate the killer cell immunoglobulin-like receptors (KIRs) as a marker for the development of thrombocytopenia secondary to Peg-interferon (IFN) therapy in a cohort of human immunodeficiency virus (HIV)/hepatitis C virus (HCV) co-infected patients. Patients were naive to HCV treatment, receiving a first course of Peg-IFN/Ribavirin combination therapy. Total platelet count (cells ml^-1) was determined at each visit, determining platelet decline from baseline to weeks 1, 2, 4, 8 and 12 after starting therapy. The end point of the study was development of thrombocytopenia, defined as a platelet count of <1 50 000 cells ml^-1. Fifty-eight HIV/HCV co-infected patients were included in the study, of whom 20 (34.4%) developed thrombocytopenia. The absence of KIR2DS2 was associated with higher and faster rate of thrombocytopenia (54.2% vs 22.5%; P=0.012; 6.6 vs 10.3 weeks; P=0.008). The absence of KIR2DS2 was associated with a greater decline in platelet count and development of thrombocytopenia during Peg-IFN treatment in HIV/HCV co-infected patients.

Longitudinal evaluation of hepatitis C viral persistence in HIV-infected patients with spontaneous hepatitis C clearance

Hepatitis C virus (HCV) viral persistence in patients with spontaneous viral clearance is controversial. Several studies have shown HCV-RNA in peripheral blood mononuclear cells (PBMCs) and/or liver tissue among patients who have cleared the virus spontaneously, suggesting that viral persistence is a common situation that could involve the entire population studied. Thus, our aim was to evaluate HCV-RNA persistence in PBMCs and hepatocytes in subjects infected with the human immunodeficiency virus (HIV). A total of 1508 patients were prospectively followed and tested for anti-HCV antibodies and HCV-RNA to identify the patients who achieved spontaneous viral clearance. In all of the patients, the persistence of HCV-RNA in PBMCs was evaluated longitudinally during 2 years of follow-up. Fifty-nine patients fulfilled the inclusion/exclusion criteria and were included in the study. HCV-RNA was not detected in the PBMCs at baseline [59 PBMCs samples tested; 0 %; 95 % confidence interval (CI): 0-3.3 %] or during the follow-up (147 PBMCs samples tested; 0 %; 95 % CI: 0-2.02 %). Our study shows that HCV viral persistence is not a frequent occurrence in HIV-infected patients who have spontaneously resolved an HCV infection. Thus, the lack of serum HCV-RNA should continue to be addressed as the standard of healing.

Therapeutic potential of HDL in cardioprotection and tissue repair

Epidemiological studies support a strong association between high-density lipoprotein (HDL) cholesterol levels and heart failure incidence. Experimental evidence from different angles supports the view that low HDL is unlikely an innocent bystander in the development of heart failure. HDL exerts direct cardioprotective effects, which are mediated via its interactions with the myocardium and more specifically with cardiomyocytes. HDL may improve cardiac function in several ways. Firstly, HDL may protect the heart against ischaemia/reperfusion injury resulting in a reduction of infarct size and thus in myocardial salvage. Secondly, HDL can improve cardiac function in the absence of ischaemic heart disease as illustrated by beneficial effects conferred by these lipoproteins in diabetic cardiomyopathy. Thirdly, HDL may improve cardiac function by reducing infarct expansion and by attenuating ventricular remodelling post-myocardial infarction. These different mechanisms are substantiated by in vitro, ex vivo, and in vivo intervention studies that applied treatment with native HDL, treatment with reconstituted HDL, or human apo A-I gene transfer. The effect of human apo A-I gene transfer on infarct expansion and ventricular remodelling post-myocardial infarction illustrates the beneficial effects of HDL on tissue repair. The role of HDL in tissue repair is further underpinned by the potent effects of these lipoproteins on endothelial progenitor cell number, function, and incorporation, which may in particular be relevant under conditions of high endothelial cell turnover. Furthermore, topical HDL therapy enhances cutaneous wound healing in different models. In conclusion, the development of HDL-targeted interventions in these strategically chosen therapeutic areas is supported by a strong clinical rationale and significant preclinical data.

Role of NADPH oxidase isoforms NOX1, NOX2 and NOX4 in myocardial ischemia/reperfusion injury

Myocardial reperfusion injury is mediated by several processes including increase of reactive oxygen species (ROS). The aim of the study is to identify potential sources of ROS contributing to myocardial ischemia-reperfusion injury. For this purpose, we investigated myocardial ischemia/reperfusion pathology in mice deficient in various NADPH oxidase isoforms (Nox1, Nox2, Nox4, as well as Nox1/2 double knockout). Following 30min of ischemia and 24h of reperfusion, a significant decrease in the size of myocardial infarct was observed in Nox1-, Nox2- and Nox1/Nox2-, but not in Nox4-deficient mice. However, no protection was observed in a model of chronic ischemia, suggesting that NOX1 and NOX2-mediated oxidative damage occurs during reperfusion. Cardioprotective effect of Nox1 and Nox2 deficiencies was associated with decrease of neutrophil invasion, but, on the other hand an improved reperfusion injury was also observed in isolated perfused hearts (Langendorff model) suggesting that inflammatory cells were not the major source of oxidative damage. A decrease in global post-reperfusion oxidative stress was clearly detected in Nox2-, but not in Nox1-deficient hearts. Analysis of key signaling pathways during reperfusion suggests distinct cardioprotective patterns: increased phosphorylation was seen for Akt and Erk in Nox1-deficient mice and for Stat3 and Erk in Nox2-deficient mice. Consequently, NOX1 and NOX2 represent interesting drug targets for controlling reperfusion damage associated with revascularization in coronary disease.

Interplay between SAFE and RISK pathways in sphingosine-1-phosphate-induced cardioprotection

PURPOSE

We studied the role of two powerful molecular signalling mechanisms involved in the cardioprotective effect of sphingosine-1-phosphate (S1P), a major component of high density lipoprotein (HDL) against myocardial ischaemic-reperfusion injury, namely the RISK pathway (Akt/Erk), including its downstream target FOXO-1 and, the SAFE pathway (TNF/STAT-3).

METHODS

Control hearts from wildtype, TNF deficient (TNF(-/-)) or cardiomyocyte STAT-3 deficient (STAT-3(-/-)) male mice were perfused on a Langendorff apparatus (35 min global ischaemia and 45 min reperfusion). S1P (10 nM) was given at the onset of reperfusion for the first 7 min, with/without STAT-3 or Akt inhibitors, AG490 and wortmannin (W), respectively.

RESULTS

S1P reduced myocardial infarct size in wildtype hearts (39.3±4.4% in control vs 17.3±3.1% in S1P-treated hearts; n≥6; p<0.05) but not in STAT-3(-/-) or TNF(-/-) mice (34.2±4.3% in STAT-3(-/-) and 34.1±2.0% in TNF(-/-) mice; n≥6; p=ns vs. their respective control). Both STAT-3 and Akt inhibitors abolished the protective effects of S1P (33.7±3.3% in S1P + AG490 and 36.6±4.9% in S1P + W; n=6; p=ns vs. their respective control). Increased nuclear levels of phosphorylated STAT-3 (pSTAT-3), Akt and FOXO-1 were observed at 15 min reperfusion in wildtype mice with Western Blot analysis (53% STAT-3, 47% Akt, 41% FOXO-1; p<0.05 vs control) but not in STAT-3-/- mice or in wiltype hearts treated with the Akt inhibitor. Interestingly, an activation of pSTAT-3 was noticed in the mitochondria at 7 min but not 15 min of reperfusion.

CONCLUSIONS

In conclusion, S1P activates both the SAFE and RISK pathways, therefore suggesting a dual protective signalling in S1P-induced cardioprotection.

HDLs protect pancreatic β-cells against ER stress by restoring protein folding and trafficking

Endoplasmic reticulum (ER) homeostasis alteration contributes to pancreatic β-cell dysfunction and death and favors the development of diabetes. In this study, we demonstrate that HDLs protect β-cells against ER stress induced by thapsigargin, cyclopiazonic acid, palmitate, insulin overexpression, and high glucose concentrations. ER stress marker induction and ER morphology disruption mediated by these stimuli were inhibited by HDLs. Using a temperature-sensitive viral glycoprotein folding mutant, we show that HDLs correct impaired protein trafficking and folding induced by thapsigargin and palmitate. The ability of HDLs to protect β-cells against ER stress was inhibited by brefeldin A, an ER to Golgi trafficking blocker. These results indicate that HDLs restore ER homeostasis in response to ER stress, which is required for their ability to promote β-cell survival. This study identifies a cellular mechanism mediating the beneficial effect of HDLs on β-cells against ER stress-inducing factors.

Ca 15.3 in breast cancer: comparison of two assays and validation in a Mexican population

Ca 15.3 is a tumor marker used for breast carcinoma, since one epitope is an antigen present in milk fat globules. Serum from 171 patients with breast cancer upon initial presentation was studied for Ca 15.3. In the first 72 cases, the authors compared RIA vs. ELISA using a simple linear regression. On the following 99, only ELISA was performed. With all 171 patients, a clinical association between Ca 15.3 measurement and age, stage and hormone receptors was carried out. Correlation coefficient between RIA and ELISA was 0.85. Of 104 patients below 50 years of age, 88 had normal Ca 15.3 and 16, elevated; 67 were older than 50 years, 46 had normal Ca 15.3 and 21, elevated (p=0.022). Ca 15.3 was elevated in 11% of patients with clinical stages I/II, and 89% in stages III/IV (p=0.0001). The association of Ca 15.3 with hormone receptors was not significant. In conclusion, ELISA and RIA measure Ca 15.3 with comparable results, the first method has the advantage of not using radioactivity. The authors found higher probability of elevated Ca 15.3 in older patients and in those with advanced disease.

Analysis of costs in a pediatric ICU

OBJECTIVE

To analyze the actual cost of pediatric intensive care and its different components, particularly the differences between various patient groups, with special reference to the variable cost and the elements included in it.

DESIGN

Prospective, observational study.

SETTING

Multidisciplinary 12-bed pediatric intensive care unit (PICU) in a tertiary university hospital.

PATIENTS

495 admissions to the unit over 17 consecutive months; 64.2% were medical patients and 35.8% were surgical patients; the mean (SE) stay in the PICU was 6.6 +/- 0.4 days.

MEASUREMENTS AND RESULTS

The fixed cost per day per patient was calculated, including the costs of physicians, nurses, auxiliary and other personnel who worked during the study period, and the costs of structural depreciation, maintenance, consumption, and disposable material. The variable cost was individually calculated from the costs of routine procedures and also included expenditure on pharmaceuticals, blood products, biochemical, hematological, and bacteriologic tests, radiology, image diagnosis procedures, and other procedures. The Physiologic Stability Index (PSI) was obtained in the first 24 h after admission. The mean fixed cost per patient per day was u.s. $608, which represents 72% of the total patient cost during this study; 86% of this amount was for personnel (58% for nurses and auxiliary staff). Variable costs came to 28% of the total amount, and were $218 +/- 100 (M +/- SEM) per patient per day. In addition to the costs of their longer stay in the PICU, the daily variable costs of nonsurvivors were higher than those of survivors ($542 +/- 52 vs $179 +/- 7; p < 0.001). We classified the patients into four groups according to their PSI score in the first 24 h; variable daily costs increased (p < 0.05) in all comparisons with the PSI level: group I: < 4 points ($155 +/- 0.5), group II: 5-9 points ($210 +/- 13), group III: 10-14 points ($324 +/- 54), group IV: > 15 points ($480 +/- 42). However, this pattern was not found for all resources: the cost of treatment techniques and biochemical and hematological tests increased, but the consumption of antibiotics, parenteral nutrition, blood products, and bacteriologic tests reached their maximum level in groups I-III and radiology was not significantly influenced by PSI level.

CONCLUSIONS

The cost of personnel was the biggest factor in intensive care costs: 62.4% of the total costs. Nonsurvivors generated 3 times the mean variable daily expenditure on survivors and had longer stays in the PICU. The increase in PSI score on the first day was associated with a global increase in variable costs. The cost of treatment techniques significantly increased as the illness became more severe but consumption of antibiotics and parenteral nutrition and use of bacteriologic tests and radiology did not.

Staging and treatment of nasopharyngeal angiofibroma

To analyze the prognostic value of clinical-radiologic staging, morbidity, mortality and results of treatment used in the Instituto Nacional de Cancerologia, Mexico, a retrospective study of angiofibroma was performed. Charts were reviewed from patients who attended the institute from 1977 to 1993. History and physical examination, rhinoscopy and fiber-optic nasopharyngolaryngoscopy were done in every patient. Radiologic evaluation was done with computed tomography, after which Chandler's staging system was used. Disease-free interval curves were estimated for patients who had presented with stage III or IV tumors. Thirty-one patients were treated with surgery and/or radiotherapy. Most of the patients had stage III (70.9%) or stage JV (25.8%) disease. Surgical procedures included lateral rhinotomies (15 cases), transpalatal dissections (11 cases), transantral degloving (3 cases), median rhinotomies (2 cases), infratemporal transzygomatic dissections (2 cases), frontotemporal craniotomy (1 case) and suprahyoid pharyngotomy (1 case). Radiotherapy (as 3000-5500 cGy) was administered to 16 patients: 7 patients with stage III persistent or recurrent tumor and 8 patients as initial treatment for stage IV disease. The disease-free interval of patients with stage III and IV disease was 80.3% and 19%, respectively, after 36 months of follow-up. Findings demonstrated that surgery was the treatment chosen in patients with stage II and III disease, with low morbidity and mortality, and good results in disease control. In contrast, radiotherapy was usually the treatment in stage IV disease, but had low effectiveness, indicating the need to carefully investigate the value of craniofacial approaches in these tumors.