Caroline Guzman

Consequences of increasing convection onto patient care and protein removal in hemodialysis

Introduction Recent randomised controlled trials suggest that on-line hemodiafiltration (OL-HDF) improves survival, provided that it reaches high convective volumes. However, there is scant information on the feasibility and the consequences of modifying convection volumes in clinics. Methods Twelve stable dialysis patients were treated with high-flux 1.8 m2 polysulphone dialyzers and 4 levels of convection flows (QUF) based on GKD-UF monitoring of the system, for 1 week each. The consequences on dialysis delivery (transmembrane pressure (TMP), number of alarms, % of achieved prescribed convection) and efficacy (mass removal of low and high molecular weight compounds) were analysed. Results TMP increased exponentially with QUF (p<0.001 for N >56,000 monitoring values). Beyond 21 L/session, this resulted into frequent TMP alarms requiring nursing staff interventions (mean ± SEM: 10.3 ± 2.2 alarms per session, p<0.001 compared to lower convection volumes). Optimal convection volumes as assessed by GKD-UF-max were 20.6 ± 0.4 L/session, whilst 4 supplementary litres were obtained in the maximum situation (24.5 ± 0.6 L/session) but the proportion of sessions achieving the prescribed convection volume decreased from 94% to only 33% (p<0.001). Convection increased high molecular weight compound removal and shifted the membrane cut-off towards the higher molecular weight range. Conclusions Reaching high convection volumes as recommended by the recent RCTs (> 20L) is feasible by setting an HDF system at its optimal conditions based upon the GKD-UF monitoring. Prescribing higher convection volumes resulted in instability of the system, provoked alarms, was bothersome for the nursing staff and the patients, rarely achieved the prescribed convection volumes and increased removal of high molecular weight compounds, notably albumin.

Influence of geography, seasons and pedology on chemical composition and anti-inflammatory activities of essential oils from Lippia multiflora Mold leaves.

ETHNOPHARMACOLOGICAL RELEVANCE Lippia multiflora is a plant with nutritional and pharmaco-therapeutic properties that is native to central and occidental Africa. The potential effects of plants on health are associated with their chemical composition. Therefore, the present study aimed to identify chemical variations in essential oils of Lippia multiflora as a function of geographic origin and time of annual harvest to determine optimal chemical profiles for ethno-pharmacotherapeutic applications. MATERIALS AND METHODS Experimental plants were cultivated at Abidjan (LPA), Toumodi (LPT) and Bondoukou (LPB). Natural Lippia multiflora seeds were sourced to produce standardized plants over a period of six months. Standard plants (n=40) were re-introduced into natural plots, cultivated for 12 months and leaves were sampled monthly in a standardized fashion. Essentials oils (n=36) were then extracted from these samples by hydro-distillation according to the European Pharmacopoeia and qualitatively and quantitatively analyzed using GC/FID and GC/MS. These data were then analyzed using Principal Component Analysis (PCA). Anti-inflammatory properties were also assessed against activated macrophages in vitro. RESULTS The results indicated that chemical profiles and essential oil yields vary according to the location where the plants were cultivated. One essential oil chemotype corresponded to the LPA and LPT sites and one corresponded to the LPB site. Statistical analysis of the chemical profiles and monthly evolution of the three sites over a period of one year allowed assessment of variations in composition and the subsequent choice of the optimal harvest time for ethnopharmacological applications. Anti-inflammatory activity apparently correlated with chemical profiles of essential oils and the geographic origins of the plants. CONCLUSION The optimal harvest time was associated with the maximum yield of pharmacological compounds with the most potential interest for health.

A reliable method to assess the water permeability of a dialysis system: the global ultrafiltration coefficient

Background: Recent randomized controlled trials suggest that sufficiently high convection post‐dilutional haemodiafiltration (HC‐HDF) improves survival in dialysis patients, consequently this technique is increasingly being adopted. However, when performing HC‐HDF, rigorous control systems of the ultrafiltration setting are required. Assessing the global ultrafiltration coefficient of the dialysis system [GKD‐UF; defined as ultrafiltration rate (QUF)/transmembrane pressure] or water permeability may be adapted to the present dialysis settings and be of value in clinics. Methods: GKD‐UF was determined and its reproducibility, variability and influencing factors were specifically assessed in 15 stable patients routinely treated by high‐flux haemodialysis or HC‐HDF in a single unit. Results: GKD‐UF invariably followed a parabolic function with increasing QUF in dialysis and both pre‐ and post‐dilution HC‐HDF (R2 constantly >0.96). The vertex of the parabola, GKD‐UF‐max and related QUF were very reproducible per patient (coefficient of variation 3.9 ± 0.6 and 3.3 ± 0.3%, respectively) and they greatly varied across patients (31‐42 mL/h−1/mmHg and 82‐100 mL/min, respectively). GKD‐UF‐max and its associated QUF decreased during dialysis treatment (P < 0.01). The GKD‐UF‐max decrease was related to weight loss (R2 = 0.66; P = 0.0015). Conclusions: GKD‐UF is a reliable and accurate method to assess the water permeability of a system in vivo. It varies according to dialysis setting and patient‐related factors. It is an objective parameter evaluating the forces driving convection and identifies any diversion of the system during the treatment procedure. It is applicable to low‐ or high‐flux dialysis as well as pre‐ or post‐dilution HDF. Thus, it may be used to describe the characteristics of a dialysis system, is suitable for clinical use and may be of help for personalized prescription.

Correction: Consequences of increasing convection onto patient care and protein removal in hemodialysis

[This corrects the article DOI: 10.1371/journal.pone.0171179.].

Adipose tissue derived-factors impaired pancreatic β-cell function in diabetes

Inflammatory factors produced and secreted by adipose tissue, in particular peri-pancreatic adipose tissue (P-WAT), may influence pancreatic β-cell dysfunction. Using the ZDF Rat model of diabetes, we show the presence of infiltrating macrophage (ED1 staining) on pancreatic tissue and P-WAT in the pre-diabetes stage of the disease. Then, when the T2D is installed, infiltrating cells decreased. Meanwhile, the P-WAT conditioned-medium composition, in terms of inflammatory factors, varies during the onset of the T2D. Using chemiarray technology, we observed an over expression of CXCL-1, -2, -3, CCL-3/MIP-1α and CXCL-5/LIX and TIMP-1 in the 9 weeks old obese ZDF pre-diabetic rat model. Surprisingly, the expression profile of these factors decreased when animals become diabetic (12 weeks obese ZDF rats). The expression of these inflammatory proteins is highly associated with inflammatory infiltrate. P-WAT conditioned-medium from pre-diabetes rats stimulates insulin secretion, cellular proliferation and apoptosis of INS-1 cells. However, inhibition of conditioned-medium chemokines acting via CXCR2 receptor do not change cellular proliferation apoptosis and insulin secretion of INS-1 cells induced by P-WAT conditioned-medium. Taken together, these results show that among the secreted chemokines, increased expression of CXCL-1, -2, -3 and CXCL-5/LIX in P-WAT conditioned-medium is concomitant with the onset of the T2D but do not exerted a direct effect on pancreatic β-cell dysfunction.

Possible Protective Effect of Membrane Lipid Rafts against Interleukin-1β-Mediated Anti-Proliferative Effect in INS-1 Cells

We recently reported that pancreatic islets from pre-diabetic rats undergo an inflammatory process in which IL-1β takes part and controls β-cell function. In the present study, using the INS-1 rat pancreatic β-cell line, we investigated the potential involvement of membrane-associated cholesterol-enriched lipid rafts in IL-1β signaling and biological effects on insulin secretion, β-cell proliferation and apoptosis. We show that, INS-1 cells exposure to increasing concentrations of IL-1β leads to a progressive inhibition of insulin release, an increase in the number of apoptotic cells and a dose-dependent decrease in pancreatic β-cell proliferation. Disruption of membrane lipid rafts markedly reduced glucose-stimulated insulin secretion but did not affect either cell apoptosis or proliferation rate, demonstrating that membrane lipid raft integrity is essential for β-cell secretory function. In the same conditions, IL-1β treatment of INS-1 cells led to a slight further decrease in insulin secretion for low concentrations of the cytokine, and a more marked one, similar to that observed in normal cells for higher concentrations. These effects occurred together with an increase in iNOS expression and surprisingly with an upregulation of tryptophane hydroxylase and protein Kinase C in membrane lipid rafts suggesting that compensatory mechanisms develop to counteract IL-1β inhibitory effects. We also demonstrate that disruption of membrane lipid rafts did not prevent cytokine-induced cell death recorded after exposure to high IL-1β concentrations. Finally, concerning cell proliferation, we bring strong evidence that membrane lipid rafts exert a protective effect against IL-1β anti-proliferative effect, possibly mediated at least partly by modifications in ERK and PKB expression/activities. Our results 1) demonstrate that IL-1β deleterious effects do not require a cholesterol-dependent plasma membrane compartmentalization of IL-1R1 signaling and 2) confer to membrane lipid rafts integrity a possible protective function that deserves to be considered in the context of inflammation and especially T2D pathogenesis.

P256 Biocommunication locale entre le tissu adipeux péripancréatique et la cellule béta pabcréatique : caractérisation immunologique

Rationnel Lors de l’obesite, les facteurs secretes par le tissu adipeux influencent la fonction et la masse β-cellulaire. Lorsque l’adiposite viscerale augmente, se developpe un tissu adipeux peri-pancreatique (TAPP), qui penetre le pancreas et etablit des contacts avec les ilots de Langerhans. Rebuffat et al (Endocrinology, 2012) ont montre dans un modele d’obesite et d’insulino-resistance que des facteurs secretes par le TAPP, modulent la proliferation des cellules β. Ceci est en faveur d’une biocommunication locale entre le TAPP et la cellule β. Notre objectif est de caracteriser le TAPP en termes de cellules immunitaires et de facteurs inflammatoires secretes lors du diabete de type 2 (DT2). Materiels et methodes Notre etude est realisee chez le rat ZDF un modele animal d’obesite et de DT2. Trois groupes d’animaux sont etudies, rats pre-diabetiques (6 et 10 semaines) et rats diabetiques (12 semaines). La presence de cellules immunitaires infiltrant le TAPP est etudiee par immunohistochimie a l’aide du marqueur macrophagique ED1. Le profil d’expression des cytokines secretees par les TAPP est analyse par la technologie de puce a anticorps (Chemiarray, RD System). Resultats Une augmentation des macrophages infiltrant le PPAT est observees chez les animaux pre-diabetiques. Parmi les cytokines/chimiokines analyses, SICAM-1, IL-1α, IP-10, L-selectine, TIMP-1, TNF et VEGF sont secretees par le TAPP independamment du stade de la pathologie. En revanche, CINC- 1, 2, 3, IL-1β, LIX, MIP-1α apparaissent uniquement dans le secretome du TAPP d’animaux pre-diabetiques (10 s). Le niveau de secretion de TIMP-1 est augmente d’un facteur 4. Conclusion Nos resultats montrent que le profil et le niveau d’expression de cytokines/chimiokines secretees par le TAPP varie du stade de pre-diabete au DT2. Ces variations (i) permettraient la mise en place et le maintien de l’inflammation en attirant des cellules immunitaires dans le TAPP et (ii) contribueraient au dysfonctionnement progressif β-cellulaire survenant dans le DT2.