Effects of adding early cooperation and a work-place dialogue meeting to primary care management for sick-listed patients with stress-related disorders: CO-WORK-CARE-Stress - a pragmatic cluster randomised controlled trial

OBJECTIVES

To investigate whether intensified cooperation between general practitioner (GP), care manager and rehabilitation coordinator (RC) for patients sick-listed for stress-related mental disorder, combined with a person-centred dialogue meeting with employer, could reduce sick-leave days compared with usual care manager contact.

DESIGN

Pragmatic cluster-randomised controlled trial, randomisation at primary care centre (PCC) level.

SETTING

PCCs in Region Västra Götaland, Sweden, with care manager organisation.

PARTICIPANTS

Of 30 invited PCCs, 28 (93%) accepted the invitation and recruited 258 patients newly sick-listed due to stress-related mental disorder (n = 142 intervention, n = 116 control PCCs).

INTERVENTION

Cooperation between GP, care manager and rehabilitation coordinator from start of illness notification plus a person-centred dialogue meeting between patient and employer within 3 months. Regular contact with care manager was continued at the control PCCs.

MAIN OUTCOME MEASURES

12-months net and gross number of sick-leave days. Secondary outcomes: Symptoms of stress, depression, anxiety; work ability and health related quality of life (EQ-5D) over 12 months.

RESULTS

There were no significant differences between intervention and control groups after 12 months: days on sick-leave (12-months net sick-leave days, intervention, mean = 110.7 days (95% confidence interval (CI) 82.6 - 138.8); control, mean = 99.1 days (95% CI 73.9 - 124.3)), stress, depression, or anxiety symptoms, work ability or EQ-5D. There were no significant differences between intervention and control groups concerning proportion on sick-leave after 3, 6, 12 months. At 3 months 64.8% were on sick-leave in intervention group vs 54.3% in control group; 6 months 38% vs 32.8%, and12 months 16.9% vs 15.5%.

CONCLUSION

Increased cooperation at the PCC between GP, care manager and RC for stress-related mental disorder coupled with an early workplace contact in the form of a person-centred dialogue meeting does not reduce days of sick-leave or speed up rehabilitation.Trial registration: ClinicalTrials.gov Identifier: NCT03250026 https://clinicaltrials.gov/study/NCT03250026?tab=results#publicationsCO-WORK-CAREFirst Posted: August 15, 2017. Recruitment of PCCs: September 2017. Inclusion of patients from December 2017.

Women's decision-making related to induced abortion - a cross sectional study during a period of Covid-19 pandemic, in Sweden

OBJECTIVES

To investigate women's decision-making on induced abortion.

MATERIALS AND METHODS

A multi-centre cross-sectional survey among 623 abortion-seeking women in Sweden (2021). The perceived difficulty to decide on abortion was measured using a 7-point Likert scale, and analysed with univariate and multivariate analysis (odds ratios [OR], 95% confidence intervals [CI]).

RESULTS

About half (n = 322;52%) scored 1-4, suggesting the decision was perceived as easier compared to those (n = 292;48%) who scored 5-7. Reasons for the abortion were: poor economy (n = 166;27%), too early in the relationship (n = 154;25.1%), want to work first (n = 147;23.9%), want to study first (n = 132;21.5%), uncertain about the relationship (104;16.9%), and too young (n = 104;16.9%). Predictors for perceiving the decision as difficult: partner's hesitance (OR = 3.18, CI:1.76-5.73), being born outside the Nordic countries (OR = 2.23, CI:1.28-3.87), having discussed the decision with someone (OR = 2.42, CI:1.67-3.50), age ≥30 (OR = 2.22, CI:1.03-4.76), the Covid-19 pandemic (OR = 2.08, CI:1.20-3.59), and the desire to have children in the future (OR = 1.96, CI:1.18-3.28). After confirmed pregnancy, poor mental well-being was more common among those who scored 5-7 (n = 140;47.9%) compared to those who scored 1-4 (n = 122;37.9), p = .029.

CONCLUSION

Women's decision-making on abortion is complex; in times of crises, the decision procedure may be even more difficult. This valuable knowledge could be used to improve and promote satisfactory counselling beyond medical routines.

Safety and efficacy of tenecteplase in patients with wake-up stroke assessed by non-contrast CT (TWIST): a multicentre, open-label, randomised controlled trial

BACKGROUND

Current evidence supports the use of intravenous thrombolysis with alteplase in patients with wake-up stroke selected with MRI or perfusion imaging and is recommended in clinical guidelines. However, access to advanced imaging techniques is often scarce. We aimed to determine whether thrombolytic treatment with intravenous tenecteplase given within 4·5 h of awakening improves functional outcome in patients with ischaemic wake-up stroke selected using non-contrast CT.

METHODS

TWIST was an investigator-initiated, multicentre, open-label, randomised controlled trial with blinded endpoint assessment, conducted at 77 hospitals in ten countries. We included patients aged 18 years or older with acute ischaemic stroke symptoms upon awakening, limb weakness, a National Institutes of Health Stroke Scale (NIHSS) score of 3 or higher or aphasia, a non-contrast CT examination of the head, and the ability to receive tenecteplase within 4·5 h of awakening. Patients were randomly assigned (1:1) to either a single intravenous bolus of tenecteplase 0·25 mg per kg of bodyweight (maximum 25 mg) or control (no thrombolysis) using a central, web-based, computer-generated randomisation schedule. Trained research personnel, who conducted telephone interviews at 90 days (follow-up), were masked to treatment allocation. Clinical assessments were performed on day 1 (at baseline) and day 7 of hospital admission (or at discharge, whichever occurred first). The primary outcome was functional outcome assessed by the modified Rankin Scale (mRS) at 90 days and analysed using ordinal logistic regression in the intention-to-treat population. This trial is registered with EudraCT (2014-000096-80), ClinicalTrials.gov (NCT03181360), and ISRCTN (10601890).

FINDINGS

From June 12, 2017, to Sept 30, 2021, 578 of the required 600 patients were enrolled (288 randomly assigned to the tenecteplase group and 290 to the control group [intention-to-treat population]). The median age of participants was 73·7 years (IQR 65·9-81·1). 332 (57%) of 578 participants were male and 246 (43%) were female. Treatment with tenecteplase was not associated with better functional outcome, according to mRS score at 90 days (adjusted OR 1·18, 95% CI 0·88-1·58; p=0·27). Mortality at 90 days did not significantly differ between treatment groups (28 [10%] patients in the tenecteplase group and 23 [8%] in the control group; adjusted HR 1·29, 95% CI 0·74-2·26; p=0·37). Symptomatic intracranial haemorrhage occurred in six (2%) patients in the tenecteplase group versus three (1%) in the control group (adjusted OR 2·17, 95% CI 0·53-8·87; p=0·28), whereas any intracranial haemorrhage occurred in 33 (11%) versus 30 (10%) patients (adjusted OR 1·14, 0·67-1·94; p=0·64).

INTERPRETATION

In patients with wake-up stroke selected with non-contrast CT, treatment with tenecteplase was not associated with better functional outcome at 90 days. The number of symptomatic haemorrhages and any intracranial haemorrhages in both treatment groups was similar to findings from previous trials of wake-up stroke patients selected using advanced imaging. Current evidence does not support treatment with tenecteplase in patients selected with non-contrast CT.

FUNDING

Norwegian Clinical Research Therapy in the Specialist Health Services Programme, the Swiss Heart Foundation, the British Heart Foundation, and the Norwegian National Association for Public Health.

The king's spice cabinet-Plant remains from Gribshunden, a 15th century royal shipwreck in the Baltic Sea

Maritime archaeological investigations of the wreck of the medieval warship Gribshunden (1495), flagship of King Hans of Denmark and Norway, have revealed diverse artifacts including exotic spices imported from far distant origins: saffron, ginger, clove, peppercorns, and almond. The special circumstances of the vessel's last voyage add unique context to the assemblage. Gribshunden and an accompanying squadron conveyed the king, courtiers, noblemen, and soldiers from Copenhagen to a political summit in Kalmar, Sweden. At that conference, Hans expected the Swedish Council to elect him king of Sweden, and thereby fulfill his ambition to reunify the Nordic region under a single crown. To achieve this, Hans assembled in his fleet and particularly aboard his flagship the people and elite cultural signifiers that would convince the Swedish delegation to accept his rule. Along the way, the ships anchored near Ronneby, Blekinge. Written sources record that an explosion and fire caused Gribshunden to sink off Stora Ekön (Great Oak Island). Exotic spices were status markers among the aristocracy in Scandinavia and around the Baltic Sea during the Middle Ages (1050-1550 CE). Until the Gribshunden finds, these extravagances have rarely or never been represented archaeologically. Evidence of their use and consumption in medieval Scandinavia has been limited to sparse written references. We present here the botanical remains from the Gribshunden shipwreck and compare them to previous archaeobotanical finds from the medieval Baltic region. These opulent status symbols traveled with a medieval king en route to a major historical event. The combination of textual and archaeological evidence allows a novel analytical view of the social environment in which these luxurious foods were consumed.

Hedonic perception of odors in children aged 5-8 years is similar across 18 countries: Preliminary data

OBJECTIVE

Olfactory preference emerges very early in life, and the sense of smell in children rapidly develops until the second decade of life. It is still unclear whether hedonic perception of odors is shared in children inhabiting different regions of the globe.

METHODS

Five-hundred ten healthy children (N = 510; n_girls = 256; n_boys = 254) aged from 5 to 8 years from 18 countries rated the pleasantness of 17 odors.

RESULTS

The hedonic perception of odors in children aged between 5 and 8 years was rather consistent across 18 countries and mainly driven by the qualities of an odor and the overall ability of children to label odorants.

CONCLUSION

Conclusions from this study, being a secondary analysis, are limited to the presented set of odors that were initially selected for the development of U-Sniff test and present null findings for the cross-cultural variability in hedonic perception of odors across 18 countries. These two major issues should be addressed in the future to either contradict or replicate the results presented herewith. This research lays fundament for posing further research questions about the developmental aspects of hedonic perception of odors and opens a new door for investigating cross-cultural differences in chemosensory perception of children.

Analysis of mammograms using artificial intelligence to predict response to neoadjuvant chemotherapy in breast cancer patients: proof of concept

Objectives

In this proof of concept study, a deep learning–based method for automatic analysis of digital mammograms (DM) as a tool to aid in assessment of neoadjuvant chemotherapy (NACT) treatment response in breast cancer (BC) was examined.

Methods

Baseline DM from 453 patients receiving NACT between 2005 and 2019 were included in the study cohort. A deep learning system, using the aforementioned baseline DM, was developed to predict pathological complete response (pCR) in the surgical specimen after completion of NACT. Two image patches, one extracted around the detected tumour and the other from the corresponding position in the reference image, were fed into a classification network. For training and validation, 1485 images obtained from 400 patients were used, and the model was ultimately applied to a test set consisting of 53 patients.

Results

A total of 95 patients (21%) achieved pCR. The median patient age was 52.5 years (interquartile range 43.7–62.1), and 255 (56%) were premenopausal. The artificial intelligence (AI) model predicted the pCR as represented by the area under the curve of 0.71 (95% confidence interval 0.53–0.90; p = 0.035). The sensitivity was 46% at a fixed specificity of 90%.

Conclusions

Our study describes an AI platform using baseline DM to predict BC patients’ responses to NACT. The initial AI performance indicated the potential to aid in clinical decision-making. In order to continue exploring the clinical utility of AI in predicting responses to NACT for BC, further research, including refining the methodology and a larger sample size, is warranted.

Key Points

• We aimed to answer the following question: Prior to initiation of neoadjuvant chemotherapy, can artificial intelligence (AI) applied to digital mammograms (DM) predict breast tumour response?

• DMs contain information that AI can make use of for predicting pathological complete (pCR) response after neoadjuvant chemotherapy for breast cancer.

• By developing an AI system designed to focus on relevant parts of the DM, fully automatic pCR prediction can be done well enough to potentially aid in clinical decision-making.

Improving smoking cessation after myocardial infarction by systematically implementing evidence-based treatment methods: a prospective observational cohort study

Background

For smokers who suffer a myocardial infarction (MI), smoking cessation is the most effective measure to reduce recurrent event risk. Still, evidence-based treatment methods for aiding smoking cessation post-MI are underused.

Purpose

To compare the odds of smoking cessation at two-months post-MI before and after implementing a set of pre-specified routines for optimization of evidence-based treatment methods for smoking cessation, with start during admission.

Methods

Structured routines for early smoking cessation counselling and treatment optimization were implemented at six cardiac rehabilitation (CR) centres in Sweden. The routines included CR nurses providing current smokers hospitalized for acute MI with short consultation, written material, and optimal dosage of nicotine replacement therapy during admission, increasing early prescription of varenicline for eligible patients, and contacting the patients by telephone 3–5 days after discharge, after which usual care CR follow-up commenced. Centres were also encouraged to strive for continuity in nurse-patient care. Patient data was retrieved from the SWEDEHEART registry and medical records. Using logistic regression, we compared the odds for smoking cessation at two-months post-MI for currently smoking patients admitted with MI (a) before (n=188, median age 60 years, 23% females) and (b) after (n=195, median age 60 years, 29% females) routine implementation. Secondary outcomes included adherence to implemented routines and the association of each routine with smoking cessation odds at two-months.

Results

In total, 159 (85%) and 179 (92%) of enrolled patients attended the two-month CR follow-up, before and after implementation of the new routines. After implementation, a significantly larger proportion of patients (65% vs 54%) were abstinent from smoking at two-months (crude OR 1.60 [1.04–2.48], p=0.034) (Figure 1). Including only those counselled during admission (n=89), 74% (vs 54%) were abstinent at two-months (crude OR 2.50 [1.42–4.41], p=0.002). After the new routine implementation patients were counselled more frequently during admission (50% vs 6%, p<0.001), prescribed varenicline at discharge or during follow-up (23% vs 7%, p<0.001), and contacted by telephone during the first week post-discharge (18% vs 2%, p<0.001), compared to before implementation. Crude and adjusted associations between each routine and smoking cessation at two-months are shown in Table 1. Entering all routines into the regression model simultaneously, being prescribed varenicline before discharge or during follow-up had the strongest independent association with smoking abstinence at two-months (adjusted OR 4.09 [1.68–10.00], p=0.002).

Conclusion

Our results support that readily available methods for aiding smoking cessation can be implemented effectively in routine practice, with possible beneficial effects on smoking cessation for the high-risk group of smoking MI patients.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Swedish Heart and Lung AssociationPfizer AB

Admission screening and cohort care decrease carbapenem resistant enterobacteriaceae in Vietnamese pediatric ICU's

Objectives

To assess if admission screening for Carbapenem Resistant Enterobacteriaceae (CRE) and cohort care can reduce CRE acquisition (CRE colonization during hospital stay), Hospital Acquired Infections (HAI), hospital-stay, mortality, and costs in three Intensive Care Units (ICU’s) at the Vietnamese National Children’s Hospital.

Method

CRE screening using rectal swabs and ChromIDCarbas elective culture at admission and if CRE negative, once weekly. Patients were treated in cohorts based on CRE colonization status.

Results

CRE colonization at baseline point-prevalence screening was 76.9% (103/134). Of 941 CRE screened at admission, 337 (35.8%) were CREpos. 694 patients met inclusion criteria. The 244 patients CRE negative at admission and screened > 2 times were stratified in 8 similar size groups (periods), based on time of admission. CRE acquisition decreased significant (OR − 3.2, p < 0.005) from 90% in period 2 (highest) to 48% in period 8 (last period). Patients with CRE acquisition compared to no CRE acquisition had a significantly higher rate of culture confirmed HAI, n = 20 (14%) vs. n = 2 (2%), longer hospital stays, 3.26 vs. 2.37 weeks, and higher total treatment costs, 2852 vs. 2295 USD.

Conclusion

Admission CRE screening and cohort care in pediatric ICU’s significantly decreased CRE acquisition, cases of HAI and duration of hospital-stay.

Pharmacological treatment with FGF21 strongly improves plasma cholesterol metabolism to reduce atherosclerosis

Aims 

Fibroblast growth factor (FGF) 21, a key regulator of energy metabolism, is currently evaluated in humans for treatment of type 2 diabetes and non-alcoholic steatohepatitis. However, the effects of FGF21 on cardiovascular benefit, particularly on lipoprotein metabolism in relation to atherogenesis, remain elusive.

Methods and results  

Here, the role of FGF21 in lipoprotein metabolism in relation to atherosclerosis development was investigated by pharmacological administration of a half-life extended recombinant FGF21 protein to hypercholesterolaemic APOE*3-Leiden.CETP mice, a well-established model mimicking atherosclerosis initiation and development in humans. FGF21 reduced plasma total cholesterol, explained by a reduction in non-HDL-cholesterol. Mechanistically, FGF21 promoted brown adipose tissue (BAT) activation and white adipose tissue (WAT) browning, thereby enhancing the selective uptake of fatty acids from triglyceride-rich lipoproteins into BAT and into browned WAT, consequently accelerating the clearance of the cholesterol-enriched remnants by the liver. In addition, FGF21 reduced body fat, ameliorated glucose tolerance and markedly reduced hepatic steatosis, related to up-regulated hepatic expression of genes involved in fatty acid oxidation and increased hepatic VLDL-triglyceride secretion. Ultimately, FGF21 largely decreased atherosclerotic lesion area, which was mainly explained by the reduction in non-HDL-cholesterol as shown by linear regression analysis, decreased lesion severity, and increased atherosclerotic plaque stability index.

Conclusion 

FGF21 improves hypercholesterolaemia by accelerating triglyceride-rich lipoprotein turnover as a result of activating BAT and browning of WAT, thereby reducing atherosclerotic lesion severity and increasing atherosclerotic lesion stability index. We have thus provided additional support for the clinical use of FGF21 in the treatment of atherosclerotic cardiovascular disease.

Consequences of undetected olfactory loss for human chemosensory communication and well-being

Olfactory perception has implications for human chemosensory communication and in a broader context, it affects well-being. However, most of the studies investigating the consequences of olfactory loss have recruited patients who have already been categorized as having a dysfunctional sense of smell and sought help in an ENT clinic. We revisit these findings by distinguishing subjects with olfactory impairment from a group of subjects who all declared a normal sense of smell when enrolling for this study. In the initial sample of 203 individuals, we found 59 to have impaired olfaction and four with marginal olfactory performance, not useful in daily life. Interestingly, we found a significant between-group difference in cognitive functioning, further supporting the notion of the relationship between cognition and olfactory performance. However, their chemosensory communication and well-being appeared not to be different from subjects with normosmia. Impaired olfactory function certainly has a severe impact on daily life but more so in individuals who are bothered with it and decide to seek treatment. The limited-to-no olfactory perception in the fraction of subjects who neither complain about it nor seek help in ENT clinics does not seem to have a major effect on their social, cognitive, emotional and health functioning. This article is part of the Theo Murphy meeting issue 'Olfactory communication in humans'.

Health-promoting factors in higher education for a sustainable working life - protocol for a multicenter longitudinal study

BACKGROUND

The World Health Organization has highlighted the importance of health promotion for health service providers in order to ensure sustainable working life for individuals involved in providing health services. Such sustainability begins when students are preparing to manage their own future health and welfare in working life. It has been suggested that universities, employees and trainee health professionals should adopt or follow a salutogenic approach that not only complements the providing of information on known health risks but also favors health promotion strategies. This paper describes the study design and data collection methods in a planned study aiming to explore health-promoting factors for a sustainable working life among students in higher education within healthcare and social work.

METHODS

This protocol describes a multicenter longitudinal study involving Swedish students on higher education programs in the healthcare and social work sectors. In 2018, the study invited students on seven education programs at six universities to participate. These programs were for qualification as: biomedical laboratory scientists (n = 121); dental hygienists (n = 87); nurses (n = 1411); occupational therapists (n = 111); physiotherapists (n = 48); radiographers (n = 60); and, social workers (n = 443). In total, 2283 students were invited to participate. Participants completed a baseline, a self-reported questionnaire including six validated instruments measuring health-promoting factors and processes. There are to be five follow-up questionnaires. Three while the students are studying, one a year after graduating, and one three years after graduating. Each questionnaire captures different health-promoting dimensions, namely: health-promoting resources (i.e. sense of coherence); occupational balance; emotional intelligence; health and welfare; social interaction; and work and workplace experiences/perceptions.

DISCUSSION

This study focuses on the vastly important aspect of promoting a sustainable working life for healthcare and social work employees. In contrast to previous studies in this area, the present study uses different, validated instruments in health promotion, taking a salutogenic approach. It is hoped that, by stimulating the implementation of new strategies, the study's findings will lead to education programs that prepare students better for a sustainable working life in healthcare and social work.

Manuring practices in the first millennium AD in southern Sweden inferred from isotopic analysis of crop remains

This study uses crop stable nitrogen isotope analysis of charred grain to explore manuring practices in arable production at the affluent regional center Uppåkra and a set of smaller surrounding sites, dating to the first millennium AD in southern Sweden. The isotopic analysis focuses on hulled barley, the principle crop in the Scandinavian Iron Age, and the minor crops: bread wheat, emmer wheat, rye and oat, are included to compare manuring practices in cultivation of other crop species during this period. A field experiment was first conducted to establish relationships between manuring and δ15N values in modern grain from known growing conditions. The data formed an interpretive framework to reconstruct past agricultural practices and manuring intensity in the archaeological study area. Our results from the ancient grains have demonstrated that barley from the early phase in the study area (AD 0-200) varies widely in its δ15N values, reflecting mixed manuring regimes. In the following periods (AD 200-1000), isotopic values are relatively high overall, indicating systematic input of manure. In this paper, we explore whether the isotopic data that indicates sustained and high manuring levels could reflect the wealth of Uppåkra and its surrounding areas by showing prosperity also in its agricultural production, since intensive manuring would have required more resource and labor investments. The new crop nitrogen isotopic data shed light on the agricultural practices of a long-lived Iron Age center and its surrounding areas.

Abstract P4-14-06: A study of adverse vascular effects of adjuvant therapy with aromatase inhibitors in women with breast cancer

Background: There is a debate concerning risk of cardiovascular disease (CVD) from adjuvant therapy with aromatase inhibitors (AI). Randomized trials have indicated higher CV risk and one observational study higher risk of myocardial infarction, whereas other studies have pointed out no elevated risk. The first morphological sign of developing atherosclerosis is a thickening of the arterial intima layer, whereas in the longer perspective the media layer gets thinner - a process not captured when using conventional Carotid intima-media-thickness (CIMT). We therefore used high resolution ultrasound (HRU), to separately estimated the intima and media layers and calculate the I/M thickness ratio. A thicker intima and higher I/M thickness ratio are signs of adverse vascular effects. This principle of estimating vascular aging can strongly distinguish 70-yr old subjects with and w/o prevalent CVD, yielding C-values up to 0.90 in ROC-analysis.

Patients and Methods: We included 150 postmenopausal breast cancer women of whom 50 were treated with AI during at least 3 years, 50 with at least 3 years of tamoxifen and 50 were without endocrine therapy. Patients were investigated with non-invasive HRU (22MHz) of the common carotid artery (CCA). Non-parametric statistical methods were used, including Bootstrap quantile regression to obtain 95% confidence intervals (CI) and adjustment for potential confounders: age, smoking, use of statins, HbA1c and previous HRT.

Results: Of 150 included women, 132 remained having a technically acceptable ultra sound scans and no AI therapy before tamoxifen therapy; AI (#48); tamoxifen (#40) and no anti-hormone therapy (#44). Corresponding median ages were 66, 65 and 65 yrs and median treatment durations were 54 (AI) and 58 (tamoxifen) months.

AI therapy, compared to tamoxifen, showed a significantly thicker CCA-intima layer, p = 0.031. However, mean values of both CCA-intima thickness and I/M thickness ratio were very similar in the tamoxifen and the no anti-estrogen group; Thus, AI compared to the other two groups combined, had a significantly thicker intima layer (p = 0.009) and higher I/M ratio (p = 0.047), both indicating adverse vascular effects from AI therapy. After adjustment for potential confounders, AI therapy still showed a thicker CCA intima layer of 0.015 mm (95% CI .003, .027); p = 0.016.

In contrast, corresponding analysis using conventional Carotid intima-media thickness (CIMT), revealed no significant group differences or association to AI treatment duration.

Conclusion: More than three years of adjuvant therapy with aromatase inhibitors, compared to women having no anti-estrogen therapy or tamoxifen, was associated with signs of adverse vascular effects; thicker intima layer and higher intima/media ratio of the common carotid artery. After adjustment, the thicker intima layer remained significant. These findings are in accordance with reports of increased risk of cardiovascular events following adjuvant therapy with aromatase inhibitors.

Citation Format: Lindman H, Dahlberg L, Larsson M, Naessén T. A study of adverse vascular effects of adjuvant therapy with aromatase inhibitors in women with breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-14-06.

An overview of the transport of liquid molecules through structured polymer films, barriers and composites - Experiments correlated to structure-based simulations

Films engineered to control the transport of liquids are widely used through society. Examples include barriers in packaging, wound care products, and controlled release coatings in pharmaceutics. When observed at the macroscopic scale such films commonly appear homogeneous, however, a closer look reveals a complex nano- and microstructure that together with the chemical properties of the different domains control the transport properties. In this review we compare and discuss macroscopic transport properties, measured using the straightforward, yet highly powerful technique "modified Ussing chambers", also denoted side-by-side diffusion cells, for a wide range of structured polymer films and composites. We also discuss and compare the macroscopic observations and conclusions on materials properties with that of lattice Boltzmann simulations of transport properties based on underlying material structure and chemistry. The survey of the field: (i) highlights the use and power of modified Ussing Chambers for determining liquid transport properties of polymer films, (ii) demonstrates the predictability in both directions between macroscopic observations of transport using modified Ussing chambers and structure-based simulations, and (iii) provides experimental and theoretical insights regarding the transport-determining properties of structured polymer films and composites.

NanoSIMS Analysis of Intravascular Lipolysis and Lipid Movement across Capillaries and into Cardiomyocytes

The processing of triglyceride-rich lipoproteins (TRLs) in capillaries provides lipids for vital tissues, but our understanding of TRL metabolism is limited, in part because TRL processing and lipid movement have never been visualized. To investigate the movement of TRL-derived lipids in the heart, mice were given an injection of [²H]triglyceride-enriched TRLs, and the movement of ²H-labeled lipids across capillaries and into cardiomyocytes was examined by NanoSIMS. TRL processing and lipid movement in tissues were extremely rapid. Within 30 s, TRL-derived lipids appeared in the subendothelial spaces and in the lipid droplets and mitochondria of cardiomyocytes. Enrichment of ²H in capillary endothelial cells was not greater than in cardiomyocytes, implying that endothelial cells may not be a control point for lipid movement into cardiomyocytes. Remarkably, a deficiency of the putative fatty acid transport protein CD36, which is expressed highly in capillary endothelial cells, did not impede entry of TRL-derived lipids into cardiomyocytes.

Impaired thermogenesis and sharp increases in plasma triglyceride levels in GPIHBP1-deficient mice during cold exposure

Glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1), an endothelial cell protein, binds LPL in the subendothelial spaces and transports it to the capillary lumen. In Gpihbp1^-/- mice, LPL remains stranded in the subendothelial spaces, causing hypertriglyceridemia, but how Gpihbp1^-/- mice respond to metabolic stress (e.g., cold exposure) has never been studied. In wild-type mice, cold exposure increases LPL-mediated processing of triglyceride-rich lipoproteins (TRLs) in brown adipose tissue (BAT), providing fuel for thermogenesis and leading to lower plasma triglyceride levels. We suspected that defective TRL processing in Gpihbp1^-/- mice might impair thermogenesis and blunt the fall in plasma triglyceride levels. Indeed, Gpihbp1^-/- mice exhibited cold intolerance, but the effects on plasma triglyceride levels were paradoxical. Rather than falling, the plasma triglyceride levels increased sharply (from ∼4,000 to ∼15,000 mg/dl), likely because fatty acid release by peripheral tissues drives hepatic production of TRLs that cannot be processed. We predicted that the sharp increase in plasma triglyceride levels would not occur in Gpihbp1^-/-Angptl4^-/- mice, where LPL activity is higher and baseline plasma triglyceride levels are lower. Indeed, the plasma triglyceride levels in Gpihbp1^-/-Angptl4^-/- mice fell during cold exposure. Metabolic studies revealed increased levels of TRL processing in the BAT of Gpihbp1^-/-Angptl4^-/- mice.

Copper removal from acid mine drainage-polluted water using glutaraldehyde-polyethyleneimine modified diatomaceous earth particles

Mine waters and tailings generated from mining and mineral processing activities often have detrimental impact on the local environment. One example is acid mine drainage, in which sulphides in the mining waste react with water and oxygen to produce an acidic environment that subsequently dissolves host rock minerals from the waste containing toxic metals and trace elements. Copper is one such metal of significance, as it is mined at large volumes in sulphide containing ores. It has strong biocidal activity that greatly affects ecosystems. We have previously reported that glutaraldehyde (GA)-crosslinked polyethyleneimine (PEI) has strong affinity and selectivity for copper and that diatomaceous earth (DE) particles can be modified with the material to form a copper-extraction resin. In this study, the copper uptake of GA-PEI-DE particles was investigated from synthetic and real acid mine drainage samples under different pHs and their copper removal performance was compared with that of selected commercial resins. The results revealed that copper could effectively and preferentially bind to the material at pH 4, and that the copper could be completely eluted by lowering of the pH. In addition, effective copper uptake and elution was demonstrated using real legacy acid mine drainage water from Mount Lyell in Tasmania.

Bio-template assisted synthesis of porous glutaraldehyde-polyethyleneimine particulate resin for selective copper ion binding and recovery

Porous ion-exchange resins with features of high selectivity, high capacity, fast adsorption kinetics and chemical stability over a wide pH range are attractive for extracting precious metals like copper and upcycling waste. In this study, porous glutaraldehyde-polyethyleneimine (GA-PEI) particulate resin was synthesised using diatomaceous earth (DE) particles as a bio-template. The crosslinking of PEI by GA was successfully conducted on the surface of DE. Removal of the template DE, merely by chemical etching with potassium hydroxide, resulted in the porous GA-PEI particulate resin. The resin showed excellent selectivity for copper ions in binding and recovery from solutions as complex as real legacy acid mine drainage liquid. The copper ion uptake capacity of the GA-PEI resin was determined to be >8 times greater than non-etched GA-PEI-DE particles. Under the investigated conditions, the GA-PEI resin showed higher selectivity to copper ions from real legacy acid mine drainage liquid compared to the commercial resins Purolite S930 Plus and Lewatit TP 220. Importantly, the absorbed copper ions could be released by simply adjusting pH of the solution to 1. For uptake from acid mine drainage liquid at pH 4 and elution at pH 1, purer copper solutions were achieved with GA-PEI compared to Purolite S930 Plus or Lewatit TP 220 following two cycles of iteration. The results indicate the great potential for using the porous GA-PEI resin in copper extraction under real-world conditions.

Porous ion-exchange resins with features of high selectivity, high capacity, fast adsorption kinetics and chemical stability over a wide pH range are attractive for extracting precious metals like copper and upcycling waste.

Low-Energy Collisions of Protonated Enantiopure Amino Acids with Chiral Target Gases

Here we report on the gas-phase interactions between protonated enantiopure amino acids (L- and D-enantiomers of Met, Phe, and Trp) and chiral target gases [(R)- and (S)-2-butanol, and (S)-1-phenylethanol] in 0.1-10.0 eV low-energy collisions. Two major processes are seen to occur over this collision energy regime, collision-induced dissociation and ion-molecule complex formation. Both processes were found to be independent of the stereo-chemical composition of the interacting ions and targets. These data shed light on the currently debated mechanisms of gas-phase chiral selectivity by demonstrating the inapplicability of the three-point model to these interactions, at least under single collision conditions. Graphical Abstract.

Lipoprotein lipase reaches the capillary lumen in chickens despite an apparent absence of GPIHBP1

In mammals, GPIHBP1 is absolutely essential for transporting lipoprotein lipase (LPL) to the lumen of capillaries, where it hydrolyzes the triglycerides in triglyceride-rich lipoproteins. In all lower vertebrate species (e.g., birds, amphibians, reptiles, fish), a gene for LPL can be found easily, but a gene for GPIHBP1 has never been found. The obvious question is whether the LPL in lower vertebrates is able to reach the capillary lumen. Using purified antibodies against chicken LPL, we showed that LPL is present on capillary endothelial cells of chicken heart and adipose tissue, colocalizing with von Willebrand factor. When the antibodies against chicken LPL were injected intravenously into chickens, they bound to LPL on the luminal surface of capillaries in heart and adipose tissue. LPL was released rapidly from chicken hearts with an infusion of heparin, consistent with LPL being located inside blood vessels. Remarkably, chicken LPL bound in a specific fashion to mammalian GPIHBP1. However, we could not identify a gene for GPIHBP1 in the chicken genome, nor could we identify a transcript for GPIHBP1 in a large chicken RNA-seq data set. We conclude that LPL reaches the capillary lumen in chickens - as it does in mammals - despite an apparent absence of GPIHBP1.

Electroactive Polyhydroquinone Coatings for Marine Fouling Prevention-A Rejected Dynamic pH Hypothesis and a Deceiving Artifact in Electrochemical Antifouling Testing

Nanometer-thin coatings of polyhydroquinone (PHQ), which release and absorb protons upon oxidation and reduction, respectively, were tested for electrochemically induced anti-biofouling activity under the hypothesis that a dynamic pH environment would discourage fouling. Antifouling tests in artificial seawater using the marine, biofilm-forming bacterium Vibrio alginolyticus proved the coatings to be ineffective in fouling prevention but revealed a deceiving artifact from the reactive species generated at the counter electrode (CE), even for electrochemical bias potentials as low as |400| mV versus Ag|AgCl. These findings provide valuable information on the preparation of nanothin PHQ coatings and their electrochemical behavior in artificial seawater. The results further demonstrate that it is critical to isolate the CE in electrochemical anti-biofouling testing.

Apolipoprotein C-III inhibits triglyceride hydrolysis by GPIHBP1-bound LPL

apoC-III is often assumed to retard the intravascular processing of triglyceride-rich lipoproteins (TRLs) by inhibiting LPL, but that view is based largely on studies of free LPL. We now recognize that intravascular LPL is neither free nor loosely bound, but instead is tightly bound to glycosylphosphatidylinositol-anchored HDL-binding protein 1 (GPIHBP1) on endothelial cells. Here, we revisited the effects of apoC-III on LPL, focusing on apoC-III's capacity to affect the activity of GPIHBP1-bound LPL. We found that TRLs from APOC3 transgenic mice bound normally to GPIHBP1-bound LPL on cultured cells in vitro and to heart capillaries in vivo. However, the triglycerides in apoC-III-enriched TRLs were hydrolyzed more slowly by free LPL, and the inhibitory effect of apoC-III on triglyceride lipolysis was exaggerated when LPL was bound to GPIHBP1 on the surface of agarose beads. Also, recombinant apoC-III reduced triglyceride hydrolysis by free LPL only modestly, but the inhibitory effect was greater when the LPL was bound to GPIHBP1. A mutant apoC-III associated with low plasma triglyceride levels (p.A23T) displayed a reduced capacity to inhibit free and GPIHBP1-bound LPL. Our results show that apoC-III potently inhibits triglyceride hydrolysis when LPL is bound to GPIHBP1.

Association between angiogenic factors and signs of arterial aging in women with pre-eclampsia

OBJECTIVE

Pre-eclampsia (PE) is associated with an increased risk of cardiovascular disease later in life. In cases with PE there is a substantial increase in levels of the antiangiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1) and decreased levels of the proangiogenic factor placental growth factor (PlGF). Elevated levels of sFlt-1 are also found in individuals with cardiovascular disease. The aims of this study were to assess levels of sFlt-1, PlGF and the sFlt-1/PlGF ratio and their correlation with signs of arterial aging by measuring the common carotid artery (CCA) intima and media thicknesses and their ratio (I/M ratio) in women with and without PE.

METHODS

Serum sFlt-1 and PlGF levels were measured using commercially available enzyme-linked immunosorbent assay kits, and CCA intima and media thicknesses were estimated using high-frequency (22-MHz) ultrasonography in 55 women at PE diagnosis and in 64 women with normal pregnancy at a similar gestational age, with reassessment at 1 year postpartum.

RESULTS

During pregnancy, higher levels of sFlt-1, lower levels of PlGF, a thicker intima, a thinner media and a higher I/M ratio of the CCA were found in women with PE vs controls (all P < 0.0001). Further, sFlt-1 and the sFlt-1/PlGF ratio were positively correlated with intima thickness and I/M ratio (all P < 0.0001). At 1 year postpartum, levels of sFlt-1 and the sFlt-1/PlGF ratio had decreased in both groups; however, their levels in the PE group were still higher than in the controls (P = 0.001 and < 0.0001, respectively). Levels of sFlt-1 and the sFlt-1/PlGF ratio remained positively correlated with intima thickness and I/M ratio at 1 year postpartum.

CONCLUSIONS

Higher sFlt-1 levels and sFlt-1/PlGF ratio in women with PE were positively associated with signs of arterial aging during pregnancy. At 1 year postpartum, sFlt-1 levels and the sFlt-1/PlGF ratio were still higher in the PE group and were associated with the degree of arterial aging. © 2016 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Mutating a conserved cysteine in GPIHBP1 reduces amounts of GPIHBP1 in capillaries and abolishes LPL binding

Mutation of conserved cysteines in proteins of the Ly6 family cause human disease-chylomicronemia in the case of glycosylphosphatidylinositol-anchored HDL binding protein 1 (GPIHBP1) and paroxysmal nocturnal hemoglobinuria in the case of CD59. A mutation in a conserved cysteine in CD59 prevented the protein from reaching the surface of blood cells. In contrast, mutation of conserved cysteines in human GPIHBP1 had little effect on GPIHBP1 trafficking to the surface of cultured CHO cells. The latter findings were somewhat surprising and raised questions about whether CHO cell studies accurately model the fate of mutant GPIHBP1 proteins in vivo. To explore this concern, we created mice harboring a GPIHBP1 cysteine mutation (p.C63Y). The p.C63Y mutation abolished the ability of mouse GPIHBP1 to bind LPL, resulting in severe chylomicronemia. The mutant GPIHBP1 was detectable by immunohistochemistry on the surface of endothelial cells, but the level of expression was ∼70% lower than in WT mice. The mutant GPIHBP1 protein in mouse tissues was predominantly monomeric. We conclude that mutation of a conserved cysteine in GPIHBP1 abolishes the ability of GPIHBP1 to bind LPL, resulting in mislocalization of LPL and severe chylomicronemia. The mutation reduced but did not eliminate GPIHBP1 on the surface of endothelial cells in vivo.

Autoantibodies against GPIHBP1 as a Cause of Hypertriglyceridemia

BACKGROUND

A protein that is expressed on capillary endothelial cells, called GPIHBP1 (glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1), binds lipoprotein lipase and shuttles it to its site of action in the capillary lumen. A deficiency in GPIHBP1 prevents lipoprotein lipase from reaching the capillary lumen. Patients with GPIHBP1 deficiency have low plasma levels of lipoprotein lipase, impaired intravascular hydrolysis of triglycerides, and severe hypertriglyceridemia (chylomicronemia). During the characterization of a monoclonal antibody-based immunoassay for GPIHBP1, we encountered two plasma samples (both from patients with chylomicronemia) that contained an interfering substance that made it impossible to measure GPIHBP1. That finding raised the possibility that those samples might contain GPIHBP1 autoantibodies.

METHODS

Using a combination of immunoassays, Western blot analyses, and immunocytochemical studies, we tested the two plasma samples (as well as samples from other patients with chylomicronemia) for the presence of GPIHBP1 autoantibodies. We also tested the ability of GPIHBP1 autoantibodies to block the binding of lipoprotein lipase to GPIHBP1.

RESULTS

We identified GPIHBP1 autoantibodies in six patients with chylomicronemia and found that these autoantibodies blocked the binding of lipoprotein lipase to GPIHBP1. As in patients with GPIHBP1 deficiency, those with GPIHBP1 autoantibodies had low plasma levels of lipoprotein lipase. Three of the six patients had systemic lupus erythematosus. One of these patients who had GPIHBP1 autoantibodies delivered a baby with plasma containing maternal GPIHBP1 autoantibodies; the infant had severe but transient chylomicronemia. Two of the patients with chylomicronemia and GPIHBP1 autoantibodies had a response to treatment with immunosuppressive agents.

CONCLUSIONS

In six patients with chylomicronemia, GPIHBP1 autoantibodies blocked the ability of GPIHBP1 to bind and transport lipoprotein lipase, thereby interfering with lipoprotein lipase-mediated processing of triglyceride-rich lipoproteins and causing severe hypertriglyceridemia. (Funded by the National Heart, Lung, and Blood Institute and the Leducq Foundation.).

Aromatic residues in the C terminus of apolipoprotein C-III mediate lipid binding and LPL inhibition

Plasma apoC-III levels correlate with triglyceride (TG) levels and are a strong predictor of CVD outcomes. ApoC-III elevates TG in part by inhibiting LPL. ApoC-III likely inhibits LPL by competing for lipid binding. To probe this, we used oil-drop tensiometry to characterize binding of six apoC-III variants to lipid/water interfaces. This technique monitors the dependence of lipid binding on surface pressure, which increases during TG hydrolysis by LPL. ApoC-III adsorption increased surface pressure by upward of 18 mN/m at phospholipid/TG/water interfaces. ApoC-III was retained to high pressures at these interfaces, desorbing at 21-25 mN/m. Point mutants, which substituted alanine for aromatic residues, impaired the lipid binding of apoC-III. Adsorption and retention pressures decreased by 1-6 mN/m in point mutants, with the magnitude determined by the location of alanine substitutions. Trp42 was most critical to mediating lipid binding. These results strongly correlate with our previous results, linking apoC-III point mutants to increased LPL binding and activity at lipid surfaces. We propose that aromatic residues in the C-terminal half of apoC-III mediate binding to TG-rich lipoproteins. Increased apoC-III expression in the hypertriglyceridemic state allows apoC-III to accumulate on lipoproteins and inhibit LPL by preventing binding and/or access to substrate.

Caretakers' barriers to pediatric antiretroviral therapy adherence in Vietnam - A qualitative and quantitative study

BACKGROUND

Poor antiretroviral therapy (ART) adherence leads to drug resistance and treatment failures. The options for second and third line ART regimens, particularly for pediatric patients, are very limited in low and middle-income countries. HIV-infected children are mostly passive drug-takers, thus caretakers play a very important role in assuring ART adherence. Pediatric ART adherence is still a challenging problem in Vietnam since non-adherence is the major risk factor for treatment failure. Our study explores and measures caretakers' barriers in order to improve pediatric ART adherence in future.

METHODS

Exploring caretakers' barriers was conducted through a qualitative study with Focus Group Discussion (FGD) on two topics: 1. Current society - family support and difficulties in taking care children under ART; 2. Stigma experience. Based on the finding from the qualitative study a quantitative study measuring caretakers' barriers was conducted through a designed questionnaire. Study methods strictly followed the consolidated criteria with 32-item checklist for interviews and focus groups.

RESULTS

In total eight FGDs with 53 participants were conducted. Common caretakers' barriers to children's ART adherence, were financial burden, lack of ART KP (Knowledge-Practice), stigma, depression, shifting caretaker, drug taste and side effects, lack of family support, fixed health check-up schedule and HIV non-disclosure. In the questionnaire study a total of 209 caretakers participated. The most commonly reported caretakers' barriers were: financial burden (144; 69%), KP burden (143; 68%), depression (85; 41%) and stigma (30; 14.8%). Some caretakers' characteristics that significantly associated with reported barriers (p<0.05). Rural caretakers reported significantly more financial burden (OR=2.26) and stigma (OR=3.53) than urban. Caretakers with under high school level education reported significantly more financial burdens (OR=2.08) and stigma (OR=4.15) compared to caretakers with high school education or over.

CONCLUSION

Financial burden, KP burden, depression and stigma were common reported caretakers' barriers to pediatric ART adherence. Family residence, caretaker's education level and job were considered as the key factors determining caretakers' barriers related to financial burden and stigma. These findings may be important for policy makers and researchers in order to develop effective interventions regarding to caretakers' burdens and associated factors. Furthermore, a tool for nurses in monitoring caretakers' barriers to pediatric ART adherence was developed first with FDG, and then interview questionnaire. This tool could be applied and modified easily in any pediatric ART clinic settings in accordance to economic, social and cultural circumstances.

Unhindered copper uptake by glutaraldehyde-polyethyleneimine coatings in an artificial seawater model system with adsorbed swollen polysaccharides and competing ligand EDTA

Shortly after a surface is submerged in the sea, a conditioning film is generally formed by adsorption of organic molecules, such as polysaccharides. This could affect transport of molecules and ions between the seawater and the surface. An artificial seawater model system was developed to understand how adsorbed polysaccharides impact copper binding by glutaraldehyde-crosslinked polyethyleneimine coatings. Coating performance was also determined when competed against copper-chelating EDTA. Polysaccharide adsorption and copper binding and distribution were investigated using advanced analytical techniques, including depth-resolved time-of-flight secondary ion mass spectroscopy, grazing incidence X-ray absorption near-edge spectroscopy, quartz crystal microbalance with dissipation monitoring and X-ray photoelectron spectroscopy. In artificial seawater, the polysaccharides adsorbed in a swollen state that copper readily penetrated and the glutaraldehyde-polyethyleneimine coatings outcompeted EDTA for copper binding. Furthermore, the depth distribution of copper species was determined with nanometre precision. The results are highly relevant for copper-binding and copper-releasing materials in seawater.

The angiopoietin-like protein ANGPTL4 catalyzes unfolding of the hydrolase domain in lipoprotein lipase and the endothelial membrane protein GPIHBP1 counteracts this unfolding

Lipoprotein lipase (LPL) undergoes spontaneous inactivation via global unfolding and this unfolding is prevented by GPIHBP1 (Mysling et al., 2016). We now show: (1) that ANGPTL4 inactivates LPL by catalyzing the unfolding of its hydrolase domain; (2) that binding to GPIHBP1 renders LPL largely refractory to this inhibition; and (3) that both the LU domain and the intrinsically disordered acidic domain of GPIHBP1 are required for this protective effect. Genetic studies have found that a common polymorphic variant in ANGPTL4 results in lower plasma triglyceride levels. We now report: (1) that this ANGPTL4 variant is less efficient in catalyzing the unfolding of LPL; and (2) that its Glu-to-Lys substitution destabilizes its N-terminal α-helix. Our work elucidates the molecular basis for regulation of LPL activity by ANGPTL4, highlights the physiological relevance of the inherent instability of LPL, and sheds light on the molecular defects in a clinically relevant variant of ANGPTL4.

DOI:http://dx.doi.org/10.7554/eLife.20958.001

Monoclonal antibodies that bind to the Ly6 domain of GPIHBP1 abolish the binding of LPL

GPIHBP1, an endothelial cell protein, binds LPL in the interstitial spaces and shuttles it to its site of action inside blood vessels. For years, studies of human GPIHBP1 have been hampered by an absence of useful antibodies. We reasoned that monoclonal antibodies (mAbs) against human GPIHBP1 would be useful for 1) defining the functional relevance of GPIHBP1's Ly6 and acidic domains to the binding of LPL; 2) ascertaining whether human GPIHBP1 is expressed exclusively in capillary endothelial cells; and 3) testing whether GPIHBP1 is detectable in human plasma. Here, we report the development of a panel of human GPIHBP1-specific mAbs. Two mAbs against GPIHBP1's Ly6 domain, RE3 and RG3, abolished LPL binding, whereas an antibody against the acidic domain, RF4, did not. Also, mAbs RE3 and RG3 bound with reduced affinity to a mutant GPIHBP1 containing an Ly6 domain mutation (W109S) that abolishes LPL binding. Immunohistochemistry studies with the GPIHBP1 mAbs revealed that human GPIHBP1 is expressed only in capillary endothelial cells. Finally, we created an ELISA that detects GPIHBP1 in human plasma. That ELISA should make it possible for clinical lipidologists to determine whether plasma GPIHBP1 levels are a useful biomarker of metabolic or vascular disease.

Signatures of Hyperfine, Spin-Orbit, and Decoherence Effects in a Pauli Spin Blockade

We detect in real time interdot tunneling events in a weakly coupled two-electron double quantum dot in GaAs. At finite magnetic fields, we observe two characteristic tunneling times T_{d} and T_{b}, belonging to, respectively, a direct and a blocked (spin-flip-assisted) tunneling. The latter corresponds to the lifting of a Pauli spin blockade, and the tunneling times ratio η=T_{b}/T_{d} characterizes the blockade efficiency. We find pronounced changes in the behavior of η upon increasing the magnetic field, with η increasing, saturating, and increasing again. We explain this behavior as due to the crossover of the dominant blockade-lifting mechanism from the hyperfine to spin-orbit interactions and due to a change in the contribution of the charge decoherence.

Mobility of "HSPG-bound" LPL explains how LPL is able to reach GPIHBP1 on capillaries

In mice lacking glycosylphosphatidylinositol-anchored high density lipoprotein binding protein 1 (GPIHBP1), the LPL secreted by adipocytes and myocytes remains bound to heparan sulfate proteoglycans (HSPGs) on all cells within tissues. That observation raises a perplexing issue: Why isn't the freshly secreted LPL in wild-type mice captured by the same HSPGs, thereby preventing LPL from reaching GPIHBP1 on capillaries? We hypothesized that LPL-HSPG interactions are transient, allowing the LPL to detach and move to GPIHBP1 on capillaries. Indeed, we found that LPL detaches from HSPGs on cultured cells and moves to: 1) soluble GPIHBP1 in the cell culture medium; 2) GPIHBP1-coated agarose beads; and 3) nearby GPIHBP1-expressing cells. Movement of HSPG-bound LPL to GPIHBP1 did not occur when GPIHBP1 contained a Ly6 domain missense mutation (W109S), but was almost normal when GPIHBP1's acidic domain was mutated. To test the mobility of HSPG-bound LPL in vivo, we injected GPIHBP1-coated agarose beads into the brown adipose tissue of GPIHBP1-deficient mice. LPL moved quickly from HSPGs on adipocytes to GPIHBP1-coated beads, thereby depleting LPL stores on the surface of adipocytes. We conclude that HSPG-bound LPL in the interstitial spaces of tissues is mobile, allowing the LPL to move to GPIHBP1 on endothelial cells.

Dual drug-loaded biofunctionalized amphiphilic chitosan nanoparticles: Enhanced synergy between cisplatin and demethoxycurcumin against multidrug-resistant stem-like lung cancer cells

Lung cancer kills more humans than any other cancer and multidrug resistance (MDR) in cancer stem-like cells (CSC) is emerging as a reason for failed treatments. One concept that addresses this root cause of treatment failure is the utilization of nanoparticles to simultaneously deliver dual drugs to cancer cells with synergistic performance, easy to envision - hard to achieve. (1) It is challenging to simultaneously load drugs of highly different physicochemical properties into one nanoparticle, (2) release kinetics may differ between drugs and (3) general requirements for biomedical nanoparticles apply. Here self-assembled nanoparticles of amphiphilic carboxymethyl-hexanoyl chitosan (CHC) were shown to present nano-microenvironments enabling simultaneous loading of hydrophilic and hydrophobic drugs. This was expanded into a dual-drug nano-delivery system to treat lung CSC. CHC nanoparticles were loaded/chemically modified with the anticancer drug cisplatin and the MDR-suppressing Chinese herbal extract demethoxycurcumin, followed by biofunctionalization with CD133 antibody for enhanced uptake by lung CSC, all in a feasible one-pot preparation. The nanoparticles were characterized with regard to chemistry, size, zeta potential and drug loading/release. Biofunctionalized and non-functionalized nanoparticles were investigated for uptake by lung CSC. Subsequently the cytotoxicity of single and dual drugs, free in solution or in nanoparticles, was evaluated against lung CSC at different doses. From the dose response at different concentrations the degree of synergy was determined through Chou-Talalay's Plot. The biofunctionalized nanoparticles promoted synergistic effects between the drugs and were highly effective against MDR lung CSC. The efficacy and feasible one-pot preparation suggests preclinical studies using relevant disease models to be justified.

A genome-wide association study of kynurenic acid in cerebrospinal fluid: implications for psychosis and cognitive impairment in bipolar disorder

Elevated cerebrospinal fluid (CSF) levels of the glia-derived N-methyl-D-aspartic acid receptor antagonist kynurenic acid (KYNA) have consistently been implicated in schizophrenia and bipolar disorder. Here, we conducted a genome-wide association study based on CSF KYNA in bipolar disorder and found support for an association with a common variant within 1p21.3. After replication in an independent cohort, we linked this genetic variant-associated with reduced SNX7 expression-to positive psychotic symptoms and executive function deficits in bipolar disorder. A series of post-mortem brain tissue and in vitro experiments suggested SNX7 downregulation to result in a caspase-8-driven activation of interleukin-1β and a subsequent induction of the brain kynurenine pathway. The current study demonstrates the potential of using biomarkers in genetic studies of psychiatric disorders, and may help to identify novel drug targets in bipolar disorder.

An LPL-specific monoclonal antibody, 88B8, that abolishes the binding of LPL to GPIHBP1

LPL contains two principal domains: an amino-terminal catalytic domain (residues 1-297) and a carboxyl-terminal domain (residues 298-448) that is important for binding lipids and binding glycosylphosphatidylinositol-anchored high density lipoprotein binding protein 1 (GPIHBP1) (an endothelial cell protein that shuttles LPL to the capillary lumen). The LPL sequences required for GPIHBP1 binding have not been examined in detail, but one study suggested that sequences near LPL's carboxyl terminus (residues ∼403-438) were crucial. Here, we tested the ability of LPL-specific monoclonal antibodies (mAbs) to block the binding of LPL to GPIHBP1. One antibody, 88B8, abolished LPL binding to GPIHBP1. Consistent with those results, antibody 88B8 could not bind to GPIHBP1-bound LPL on cultured cells. Antibody 88B8 bound poorly to LPL proteins with amino acid substitutions that interfered with GPIHBP1 binding (e.g., C418Y, E421K). However, the sequences near LPL's carboxyl terminus (residues ∼403-438) were not sufficient for 88B8 binding; upstream sequences (residues 298-400) were also required. Additional studies showed that these same sequences are required for LPL binding to GPIHBP1. In conclusion, we identified an LPL mAb that binds to LPL's GPIHBP1-binding domain. The binding of both antibody 88B8 and GPIHBP1 to LPL depends on large segments of LPL's carboxyl-terminal domain.

Gliptin-mediated neuroprotection against stroke requires chronic pretreatment and is independent of glucagon-like peptide-1 receptor

Gliptins are anti-type 2 diabetes (T2D) drugs that regulate glycaemia by preventing endogenous glucagon-like peptide-1 (GLP-1) degradation. Chronically administered gliptins before experimental stroke can also induce neuroprotection, and this effect is potentially relevant for reducing brain damage in patients with T2D and high risk of stroke. It is not known, however, whether acute gliptin treatment after stroke (mimicking a post-hospitalization treatment) is neuroprotective or whether gliptin-mediated neuroprotection occurs via GLP-1-receptor (GLP-1R) activation. To answer these two questions, wild-type and glp-1r(-/-) mice were subjected to transient middle cerebral artery occlusion (MCAO). Linagliptin was administered acutely (50 mg/kg intravenously), at MCAO time or chronically (10 mg/kg orally) for 4 weeks before and 3 weeks after MCAO. Neuroprotection was assessed by stroke volume measurement and quantification of NeuN-positive surviving neurons. Plasma/brain GLP-1 levels and dipeptidyl peptidase-4 activity were also measured. The results show that the linagliptin-mediated neuroprotection against stroke requires chronic pretreatment and does not occur via GLP-1R. The findings provide essential new knowledge with regard to the potential clinical use of gliptins against stroke, as well as a strong impetus to identify gliptin-mediated neuroprotective mechanisms.

Angiopoietin-like 4 promotes intracellular degradation of lipoprotein lipase in adipocytes

LPL hydrolyzes triglycerides in triglyceride-rich lipoproteins along the capillaries of heart, skeletal muscle, and adipose tissue. The activity of LPL is repressed by angiopoietin-like 4 (ANGPTL4) but the underlying mechanisms have not been fully elucidated. Our objective was to study the cellular location and mechanism for LPL inhibition by ANGPTL4. We performed studies in transfected cells, ex vivo studies, and in vivo studies with Angptl4(-/-) mice. Cotransfection of CHO pgsA-745 cells with ANGPTL4 and LPL reduced intracellular LPL protein levels, suggesting that ANGPTL4 promotes LPL degradation. This conclusion was supported by studies of primary adipocytes and adipose tissue explants from wild-type and Angptl4(-/-) mice. Absence of ANGPTL4 resulted in accumulation of the mature-glycosylated form of LPL and increased secretion of LPL. Blocking endoplasmic reticulum (ER)-Golgi transport abolished differences in LPL abundance between wild-type and Angptl4(-/-) adipocytes, suggesting that ANGPTL4 acts upon LPL after LPL processing in the ER. Finally, physiological changes in adipose tissue ANGPTL4 expression during fasting and cold resulted in inverse changes in the amount of mature-glycosylated LPL in wild-type mice, but not Angptl4(-/-) mice. We conclude that ANGPTL4 promotes loss of intracellular LPL by stimulating LPL degradation after LPL processing in the ER.

The acidic domain of the endothelial membrane protein GPIHBP1 stabilizes lipoprotein lipase activity by preventing unfolding of its catalytic domain

GPIHBP1 is a glycolipid-anchored membrane protein of capillary endothelial cells that binds lipoprotein lipase (LPL) within the interstitial space and shuttles it to the capillary lumen. The LPL•GPIHBP1 complex is responsible for margination of triglyceride-rich lipoproteins along capillaries and their lipolytic processing. The current work conceptualizes a model for the GPIHBP1•LPL interaction based on biophysical measurements with hydrogen-deuterium exchange/mass spectrometry, surface plasmon resonance, and zero-length cross-linking. According to this model, GPIHBP1 comprises two functionally distinct domains: (1) an intrinsically disordered acidic N-terminal domain; and (2) a folded C-terminal domain that tethers GPIHBP1 to the cell membrane by glycosylphosphatidylinositol. We demonstrate that these domains serve different roles in regulating the kinetics of LPL binding. Importantly, the acidic domain stabilizes LPL catalytic activity by mitigating the global unfolding of LPL's catalytic domain. This study provides a conceptual framework for understanding intravascular lipolysis and GPIHBP1 and LPL mutations causing familial chylomicronemia.

DOI:http://dx.doi.org/10.7554/eLife.12095.001

Fat is an important part of our diet. The intestines absorb fats and package them into particles called lipoproteins. After reaching the bloodstream, the fat molecules (lipids) in the lipoproteins are broken down by an enzyme called lipoprotein lipase (LPL), which is located along the surface of small blood vessels. This releases nutrients that can be used by vital tissues – mainly the heart, skeletal muscle, and adipose tissues. LPL is produced by muscle and adipose tissue, but it is quickly swept up by a protein called GPIHBP1 and shuttled to its site of action inside the blood vessels.

Mutations that alter the structure of LPL or GPIHBP1 can prevent the breakdown of lipids, resulting in high levels of lipids in the blood. This can lead to inflammation in the pancreas and also increases the risk of heart attacks and strokes. Many earlier studies have examined the properties of LPL, but our understanding of GPIHBP1 has been limited, mainly because it has been difficult to purify GPIHBP1 for analysis.

Using genetically altered insect cells, Mysling et al. were able to purify two different forms of GPIHBP1 – a full-length version and a shorter version that lacked a small section at the end of the molecule known as the acidic domain. This revealed that the opposite end of the molecule – called the carboxyl-terminal domain – is primarily responsible for binding LPL and anchoring it inside blood vessels. Once LPL is bound to GPIHBP1, the acidic domain of GPIHBP1 helps to stabilize LPL. If GPIHBP1’s acidic domain is missing then LPL is more susceptible to losing its structure, rendering it incapable of breaking down the lipids in the blood.

Mysling et al. describe a new model for how LPL and GPIHBP1 interact that explains how specific mutations in the genes that encode these proteins interfere with the delivery of LPL to small blood vessels. In the future, this could help researchers to develop new strategies to treat people with high levels of lipids in their blood.

DOI:http://dx.doi.org/10.7554/eLife.12095.002