Ia); protocol numbers X09-0013 and HREC/09/RPAH/19. The clinical protocol for the collection of blood from people with diabetes and matched controls for apoA-I isolation was approved by the St Vincent’s Hospital Ethics Committee (Melbourne, Victoria, Australia). All participants gave written informed Title Loaded From File consent.ReagentsReagents were from Sigma-Aldrich (St Louis, USA) except for pre-cast gels and Chelex-100 resin (Bio-Rad, Australia), glucose (Merck, Australia), Ne-carboxymethyllysine (CML) (TRC, Canada), and 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) and 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) (Avanti Polar Lipids, Alabaster, Alabama, USA). Solutions were prepared using Nanopure water (Millipore-Waters, Australia) pre-treated with washed Chelex-100 resin to remove metal ions, with the exception of tissue culture reagents where Baxter sterile water (Old Toongabbie, Australia) or PBS were used.Characterisation of glycated apoA-IArg, Lys and Trp modification was assessed fluorometrically [25]. Protein cross-linking was determined by SDS-PAGE [9]. CML was quantified by HPLC using fluorescence detection. ApoA-I ( 400 mg protein) was precipitated using trichloroacetic acid (200 ml, 50 w/v), centrifuged (4300 g, 2 min), washed (26500 ml ice-cold acetone), re-pelleted by centrifugation (7000 g, 2 min) and dried by vacuum centrifugation. Samples were hydrolysed, derivatised using o-phthaldialdehyde, and subjected to HPLC with fluorescence detection [26]. Samples were separated (flow rate 1 ml/min) using a gradient of 85 buffer A (96 50 mM sodium acetate, pH 6.5 and 4 methanol; v/v) and 15 buffer B (100 methanol) for 35 min; 15?0 buffer B over 5 min; 90 buffer B for 2 min; 90-15 buffer B over 5 min; and re-equilibration at 15 buffer B for 8 min with buffers passing through an inline Shimadzu DGU-14A degassing unit. Identities of peaks were confirmed by spiking with authentic materials. Peak areas were converted to absolute levels using standard curves.SubjectsPeople with well-defined (American Diabetes Association guidelines) Type 1 diabetes (n = 12) without vascular complications, and who were not on any medication other than insulin, were recruited. Apparently healthy normolipidemic, non-diabetic, age and BMI-matched controls on no medication (n = 10) were also recruited (Table 1). Plasma was isolated (2000 g, 15 min, 4uC) from 80 ml of blood taken into EDTA-Na2.Glycation Alters Apolipoprotein A-I Lipid AffinityPhospholipid association assayDMPC was dissolved in a 2:1 (v/v) chloroform/methanol solution, and dried under nitrogen, before being redissolved in TBS (Tris-buffered saline) containing 8.5 KBr, 0.01 EDTA and 0.1 NaN3, at a final concentration of 0.5 mg/ml to give a turbid solution of multilamellar vesicles (MLV) [27]. MLV and apoA-I (native or modified, 0.5 mg/ml in TBS) were preincubated individually at 24uC before mixing (2.5:1 w/w) in a quartz cuvette. Samples were read at 325 nm within 15 s at 24uC using a UV-VIS spectrophotometer (UV-2550 with a TCC-240A temperaturecontrolled cell holder; Shimadzu, Kyoto, Japan) and monitored for at least 30 min [28]; MLV solubilisation (clearance) to give discoidal HDL particles decreases the absorbance at 325 nm. The presence of KBr prevents settling of the MLV during measurements. The time courses for MLV clearance were fitted by nonlinear regression (two-phase exponential decay) using Prism (Graphpad Title Loaded From File Software), after normalising the data by adjusting the initial a.Ia); protocol numbers X09-0013 and HREC/09/RPAH/19. The clinical protocol for the collection of blood from people with diabetes and matched controls for apoA-I isolation was approved by the St Vincent’s Hospital Ethics Committee (Melbourne, Victoria, Australia). All participants gave written informed consent.ReagentsReagents were from Sigma-Aldrich (St Louis, USA) except for pre-cast gels and Chelex-100 resin (Bio-Rad, Australia), glucose (Merck, Australia), Ne-carboxymethyllysine (CML) (TRC, Canada), and 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) and 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) (Avanti Polar Lipids, Alabaster, Alabama, USA). Solutions were prepared using Nanopure water (Millipore-Waters, Australia) pre-treated with washed Chelex-100 resin to remove metal ions, with the exception of tissue culture reagents where Baxter sterile water (Old Toongabbie, Australia) or PBS were used.Characterisation of glycated apoA-IArg, Lys and Trp modification was assessed fluorometrically [25]. Protein cross-linking was determined by SDS-PAGE [9]. CML was quantified by HPLC using fluorescence detection. ApoA-I ( 400 mg protein) was precipitated using trichloroacetic acid (200 ml, 50 w/v), centrifuged (4300 g, 2 min), washed (26500 ml ice-cold acetone), re-pelleted by centrifugation (7000 g, 2 min) and dried by vacuum centrifugation. Samples were hydrolysed, derivatised using o-phthaldialdehyde, and subjected to HPLC with fluorescence detection [26]. Samples were separated (flow rate 1 ml/min) using a gradient of 85 buffer A (96 50 mM sodium acetate, pH 6.5 and 4 methanol; v/v) and 15 buffer B (100 methanol) for 35 min; 15?0 buffer B over 5 min; 90 buffer B for 2 min; 90-15 buffer B over 5 min; and re-equilibration at 15 buffer B for 8 min with buffers passing through an inline Shimadzu DGU-14A degassing unit. Identities of peaks were confirmed by spiking with authentic materials. Peak areas were converted to absolute levels using standard curves.SubjectsPeople with well-defined (American Diabetes Association guidelines) Type 1 diabetes (n = 12) without vascular complications, and who were not on any medication other than insulin, were recruited. Apparently healthy normolipidemic, non-diabetic, age and BMI-matched controls on no medication (n = 10) were also recruited (Table 1). Plasma was isolated (2000 g, 15 min, 4uC) from 80 ml of blood taken into EDTA-Na2.Glycation Alters Apolipoprotein A-I Lipid AffinityPhospholipid association assayDMPC was dissolved in a 2:1 (v/v) chloroform/methanol solution, and dried under nitrogen, before being redissolved in TBS (Tris-buffered saline) containing 8.5 KBr, 0.01 EDTA and 0.1 NaN3, at a final concentration of 0.5 mg/ml to give a turbid solution of multilamellar vesicles (MLV) [27]. MLV and apoA-I (native or modified, 0.5 mg/ml in TBS) were preincubated individually at 24uC before mixing (2.5:1 w/w) in a quartz cuvette. Samples were read at 325 nm within 15 s at 24uC using a UV-VIS spectrophotometer (UV-2550 with a TCC-240A temperaturecontrolled cell holder; Shimadzu, Kyoto, Japan) and monitored for at least 30 min [28]; MLV solubilisation (clearance) to give discoidal HDL particles decreases the absorbance at 325 nm. The presence of KBr prevents settling of the MLV during measurements. The time courses for MLV clearance were fitted by nonlinear regression (two-phase exponential decay) using Prism (Graphpad Software), after normalising the data by adjusting the initial a.

Ia); protocol numbers X09-0013 and HREC/09/RPAH/19. The clinical protocol

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