Biology subjects

Tentes, I.

Publications and source records attributed to Tentes, I..

3 recordsLinked to original sources

bioRxiv2024

Erythrocyte TLR9 is upregulated in metabolic associated fatty liver disease, and is linked to an inflammatory immunometabolic signature.

Metabolic associated fatty liver disease (MAFLD) consists of lipid accumulation in the liver. Lipotoxicity, supported by aberrant amino acid metabolism, induces TLR9 upregulation, and activation, driving inflammation. Relatively, erythrocyte TLR9 activation leads to membrane rearrangement, surface CD47 loss, and pro-inflammatory erythrophagocytosis. Erythrocyte surface protein loss is accompanied by chemokine release. In addition, CD47 binds circulating TSP-1, a molecule controlling arginine and glutamine metabolism, along with metabolic inflammation. Based on these, we speculated that in MAFLD, lipotoxicity would drive erythrocyte TLR9 upregulation and activation, leading to immunometabolic remodeling. Twenty-four patients (15 men and 9 women) with MAFLD and 9 healthy controls (4 men and 5 women) were enrolled. Erythrocytes were isolated from EDTA-containing blood. Protein levels were measured in erythrocyte lysates (triton X-100 0.01% v/v) or plasma with enzyme-linked immunosorbent assays, whereas lipids and enzyme activities were measured in erythrocyte hemoglobin-free membranes by a semi-quantitative thin layer chromatography and assay kits, respectively. The levels of TLR9 were increased (p=0.002) and positively correlated with sphingosine levels, albeit not statistically significantly (p=0.060). The erythrocyte membrane PC/PE ratio was decreased (p=0.002) and inversely correlated to TLR9 levels. Erythrocyte TLR9 levels correlated inversely with CD47, and positively with MCP-1 release. TSP-1 was decreased in MAFLD erythrocytes (p=0.0017) and correlated positively with CD47 and negatively with TLR9 levels. In vitro, erythrocytes of MAFLD patients bound less TSP-1 molecules. Erythrocytes of MAFLD patients also exhibit decreased arginase-1 protein (p=0.009) and activity (p=0.042). Glutaminase activity was increased, albeit to not statistically significantly different levels (p=0.25). The levels of CD35 were not different (p=0.65), excluding the role of erythrocyte aging for explaining these events. In MAFLD patients, erythrocyte TLR9 is upregulated and is associated with erythrocyte sphingolipid and glycerophospholipid perturbation, CD47 loss, MCP1 release, reduced TSP-1 scavenging, decreased arginase and increased glutaminase.

immunology↗

bioRxiv2023

The effect of in vitro starch digestibility on glycemic/insulinemic index of biscuits and bread made from non-conventional wholemeal/wholegrain flour mixtures.

BACKGROUNDCarbohydrates as starch are a staple part of the Mediterranean diet. Starch is digested in the small intestine and the resulting glucose is absorbed into the blood, eliciting an insulin response. The digestion and absorption kinetics (rapid or slow) depends on starch structure. OBJECTIVETo study the relationship between the in vivo glycemic and insulinemic index and the in vitro digestibility characteristics of six bakery products, made from non-conventional wholemeal/wholegrain flours. METHODSWe analyzed in vitro the rapidly- and slowly- available glucose (RAG and SAG), the rapidly- and slowly- digestible starch (RDS and SDS), and the resistant starch (RS) fraction of the six wholemeal/wholegrain products and one white type of bread. The glycemic and the insulinemic index (GI and II respectively) were estimated by in vivo testing in a group of eleven healthy individuals. RESULTSThe GI of the wholemeal/wholegrain flour biscuits and breads were low, (range 28{+/-}3.2 to 41{+/-}3.9, Mean{+/-}SEM) correlating with the II. RAG positively correlated with both GI and II, with fiber having a marginal correlation. CONCLUSIONSOur findings indicate that both conventional and non-conventional wholemeal/wholegrain bakery products have low GI and moderate II, correlating to in vitro starch digestibility and the type of processing.

biochemistry↗

bioRxiv2021

Validation and Application of a Protocol for the Extraction and Quantitative Analysis of Sphingomyelin in Erythrocyte Membranes of Patients with NAFLD

A set of constituents of the erythrocyte membrane lipidome has been proposed to serve as biomarkers for liver disease and acute coronary syndrome. In erythrocytes, sphingomyelin hydrolysis provides ceramide, a signaling lipid necessary for phosphatidylserine exposure and eryptosis. Phosphatidylserine exposure further amplifies hepatic inflammation and fibrosis during non-alcoholic fatty liver disease (NAFLD). In this study, we developed and applied a quantitative TLC for erythrocyte membrane sphingomyelin of NAFLD patients. We also compared 10 extraction methods for the isolation of sphingomyelin from erythrocytes. For quantitative TLC, lipids were separated in Silica gel 60 F254 using a mixture of chloroform/methanol/acetic acid/water (60/50/1/4) (v/v/v/v). The separated lipids were stained in a chamber containing iodine, and the intensity of each of the primary colors (red, green, blue) and the sum of the Red plus Green colors (R+G) was analyzed. The method was linear over a wide range of concentrations, presented acceptable precision (inter-day CV(%) 0.34, 0.006 and 0.44 for 2.5, 5.0 and 10 g, respectively), good accuracy (recovery range 85.2-97.1%), and excellent limit of detection (0.137 g/spot) and limit of quantification (0.41 g/spot). Using this quantitation method, we compared various lipid extraction methods and found that lipid extraction with methanol led to higher yield of erythrocyte sphingomyelin (135.35{+/-}1.04% recovery, compared to the Folch method). Application of these methods showed that erythrocytes from NAFLD patients (9 men, 15 women, 57.95{+/-}11.11 years old) contained statistically significantly less sphingomyelin (829.82{+/-}511.60 vs 1892.08{+/-}606.25 g/ml of packed erythrocytes) compared to healthy controls (4 men, 6 women, 39.3{+/-}15.55 years old).

biochemistry↗