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VLDL subfractions (A-D) in type 2 diabetes: Their susceptibility to oxidation and lipid composition
Fridgv, 28 May 1999 Poster presentation: Triglyceride-rich lipoproteins and atherosclerosis vith CHD leads to their postprandial accumulation. Postprandial RLP assay luring HD is easy to do in clinical practice to identify HD patients at risk of ~therosclerosis and could be applied in other clinical settings. Atorvastatin s effective in reducing both fasting and postprandial RLP-C and RLP-TG. )YSLIPIDEMIA AS A ATHEROGENIC RISK FACTOR IN )IABETES MELLITUS
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significance. Patients V's controls: Subfraction A; 121" V's 135 min (13 = 0.05). Subfraction B; 104 V's 113 min (p = 0.345). Subfraction C; 94 V's 104 min (p = 0.106). Subfraction D; 62* V's 79 min (p = 0.037). These results show abnormalities in VLDL composition and oxidation profile from type 11 diabetes that may contribute to the development of cardiovascular disease. This work was supported by a Fournier Lipodology
Award
q_. Hancu 1,2, A. Cerghizan 2, S. lancu, L. Duma 2, A. Marian 2, A. Cota 2.
'Tuliu Hatieganu" University of Medicine and Pharmacy," 2Diabetes ?enter Cluj-Napoca, Roumania ['he objective of the study is to determine the role of dyslipidemias (DLP) in he cardiovascular risk status (CVRS) o f diabetes mellitus (DM). Four groups uere investigated: group A, 320 non insulin treated (diet and sulfonilurea) ype 2 diabetic patients, group B, 310 insulin treated type 2 diabetic patients, ;roup C, 338 type 1 diabetic patients and group D, 1240 control subjects. the patients were matched for age, gender and diabetes duration. For all ;ubjects cholesterol, triglicerides and HDL cholesterol were determined and ?VRS was assessed for according to the European Coronary Chart (1994). E)LP was diagnosed if cholesterol > 200 mg/dl, triglicerides > 150 mg/dl, md HDLchol < 35 mg/dl. Results: the most significantly prevalent condition that was found was aypercholesterolemia: 75% in group B, 66% in group A, 57.3% in group ~" and D. Hypertrigliceridemia prevalence was also high. The isolated arevalence in group B was 51.8% and in group A 36.4% in both conditions. l'he CVRS was higher in group A and B vs. groups C and D (30.2%, 24.1%, 33.4%, 25.1% vs. 9%, 12.1%, 15.4%, 14.8%). In spite of the fact that mixed ~yperlipidaemia has a lower prevalence (but not significant) the CVRS is =omparable (27.4%, 31.4%) for groups B and A. The prevalence of isolated low HDLchol is reduced but CVRS is high in these patients. Conclusion: hypercholesterolemia, hypertrigliceridemia and mixed hyperlipidaemias are serious atherogenic risk factors in DM. VLDL SUBFRACTIONS (A-D) IN TYPE 2 DIABETES: THEIR SUSCEPTIBILITY TO OXIDATION AND LIPID COMPOSITION J. McEneny "1, M.M.J. O'Kane 2, C. McMaster3, D. McMaster4, C. Mercer4, E.R. Trimble 1, I.S. Young 1. The Departments of tClinical Biochemistr),;
~Child Health; eMedicine. The Queen ~" UniuersiO; Belfast: 2AItnageluin Hospital, Dert3, N Ireland, UK The aim of this study was to determine if the dyslipidaemia associated with type II diabetes caused alterations in fatty acid and lipid distribution within VLDL subfractions. Susceptibility to copper mediated oxidation and levels of preformed peroxide were also assessed. Fifteen patients with type 11 diabetes were matched for age and sex with 15 healthy controls Four subfractions of VLDL were isolated (A-D, with A being the largest and least dense subfraction) by rapid sequential ultracentrifugation. Lipid analysis of each subfraction included MUFAs, PUFAs, SFAs, cholesterol and triglyceride. Production of conjugated dienes was used an indicator of in vitro lipid oxidation. Preformed peroxides were measured using the FOX II assay. Results show that as subfractions become smaller and more dense (A---, D), the FA profile changes. Subfractions from the control group showed that MUFAs remained constant throughout the 4 subfractions, whilst PUFAs increased and SFAs decreased. Subfractions A ~ D; MUFAs 36.8 ---,35.5%: PUFAs 21.9" ---.26.3%: SFAs 41.6" - , 38.1%. Patient subfractions showed a decrease in MUFAs and an increase in PUFAs, whilst SFAs remained constant throughout all 4 subfractions. Subfractions A ~ D; MUFAs 34.8*--, 33.0%: PUFAs 22.8*---* 26.0%: SFAs 41.9 ~ 40.8%. When FA distribution was compared between the patient and control group, the patient group had lower levels of MUFAs in all 4 subfractions. Cholesterol was higher in patient subfractions A, B&C when compared with control, Sub A: 0.07 V's 0.03*, Sub B: 0.19" V's 0.I I, Sub C: 0.13" V's 0.07 mmol/l. Triglyceride was also higher in patient subfraction A, Sub A: 0.21" V's 0.17 mmol/I (*p < 0.05). Preformed peroxides were increased in the patient group in all 4 subfractions. Patients V's controls: Subfraction A; 15.17" V's 6.58 nmol/mg protein (p --- 0.002). Subfraction B; 13.78" V's 6.27 nmol/mg protein (p = 0.006). Subfraetion C; 23.29* V's 8.83 nmol/mg protein (p = 0.002). Subfraction D; 23.46* V's 8.92 nmol/mg protein (p = 0.004). Lag time results calculated from conjugated diene measurement showed that Subfractions A and D were more easily oxidised in the patient group; lag times for subfractions B and C were also shorter in the patient group although this did not reach
INFLUENCE OF POST-PRANDIAL PHASE ON LP(a) LEVELS D. Siepi, G. Lupattelli, C. Casciari, A.R. Roscini, M. Pirro, S. Marchesi, S. Pag]]-aricci, B. Palumbo, E. Mannarino. Dept. of Clinical and Sperimental
Medicine, Internal Medicine and Angiology, Uniuersity of Perugia, Italy Many studies have shown triglyceridemia and Lp(a) levels are negatively correlated, but results are devergent on Lp(a) modification after an oral fat tolerance test (OFTT). We determined Lp(a) levels and its isoform after OFTT in n. 50 post-menopausal women: 17 with primary hypercholesterolemia (HC), 16 with mixed hypercholesterolemia (MH) and 17 normolipemic (N). Blood sample were taken after 14 hours fast and 4, 6 and 8 hours after the OFTT contaning 65 gr/m 2 fat. Lp(a) was determined by ELISA and the $4, $3, $2, SI and B isoforms by Western Blot and immunoblotting. Subjects were divided into two groups on the basis of the isoform molecular weights: low (L) those with $2, Sl and B isoforms or high (H) $4, $3 and Null Type isoforms. Subjects with double band phenotype were classificated by the dominant isoform. Median Lp(a) values were as follows: 7.3 mg/dl in N subjects, 10.9 mg/dl in MH and 25.7 mg/dl in HC. The maximum reduction in Lp(a) levels was observed at the 6th hour in N subjects (5.8 mg/dl, p < 0.01) and in MH subjects (8.5 mg/dl, p < 0.01). and at the 4th hour in HC subjects (24.8 mg/dl, p < 0.001 ) and coincided in all subjects with the triglyceride peak. The post-prandial drop in Lp(a) levels was significantly higher (p < 0.05) in H subjects comparing with L subjects indipendently of triglyceride magnitudo. Post-prandial hypertriglyceridemia reduces Lp(a) levets particulary in the presence of high molecular weight isoforms while low molecular weight isoforms appear to be less susceptible. Consequently post-prandial hyperlipemia may be considered as atherogenic agent despite the drop in Lp(a) levels.
TRYGLICERIDE-RICH-LIPOPROTEINS AND NITRIC OXIDEDEPENDENT ENDOTHELIAL FUNCTION E Ricci, L. Vergnani, N. Manzoli, P. Donega, G. Zuliani, T. Malinski, R. Fellin. Institute of Internal Medicine, Unit;ersity of Ferrara, Ferrara,
Italy: Dept of Chemist~., Oakland Uniuersit); Rochester, Michigan, USA Recent epidemiological studies suggested that hypertriglyceridemia can be accepted as a risk factor for coronary heart disease (CHD), but the mechanism behind the role of triglycerides is not yet completely understood. It is well known that one of the main marker of the endothelial dysfunction present in subjects with high risk factor for CHD is a reduced endothelialdependent relaxation. The aim of the present study was to evaluate the relation between nitric oxide (NO) production and trygliceride-rich-lipoproteins (TRL) by exposing bovine aorta endothelial cells to increasing concentration of chylomicrons and VLDL. NO production has been determined by using a porphyrinic microsensor and placing the tip o f the microsensor on the surface ofa monolayer of endothelial cells. Chylomicrons and VLDLs were obtained from human plasma of hypertriglyceridemic patients with familial hyperchyIomicronemia by density gradient ultmcentrifugation. In the first step, the endothelial cells were exposed for one hour to increasing concentration o f c'hylomicrons and VLDL. In the second step we evaluated the effect of HDL and L-arginine pre-treatment in NO production in VLDL-treated cells. NO depletion was observed and significant (p < 0.005) only at chylomicron concentration above 500 mg/dL, where NO levels were decreased to 45% of the control. In VLDL-treated cells NO level was threefold lower at the concentration of 300 mg TG/dL. L-arginine and HDL supplementation restored the NO level at all VLDL concentrations even if HDL effect was more effective. These results suggest that hyperehylomicronemia may be involved in the reduced endothelial-dependent relaxation and may act decreasing NO production and altering the L-arginine-NO system.
71st EAS Congress and Satellite Symposia
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significance. Patients V's controls: Subfraction A; 121" V's 135 min (13 = 0.05). Subfraction B; 104 V's 113 min (p = 0.345). Subfraction C; 94 V's 104 min (p = 0.106). Subfraction D; 62* V's 79 min (p = 0.037). These results show abnormalities in VLDL composition and oxidation profile from type 11 diabetes that may contribute to the development of cardiovascular disease. This work was supported by a Fournier Lipodology
Award
q_. Hancu 1,2, A. Cerghizan 2, S. lancu, L. Duma 2, A. Marian 2, A. Cota 2.
'Tuliu Hatieganu" University of Medicine and Pharmacy," 2Diabetes ?enter Cluj-Napoca, Roumania ['he objective of the study is to determine the role of dyslipidemias (DLP) in he cardiovascular risk status (CVRS) o f diabetes mellitus (DM). Four groups uere investigated: group A, 320 non insulin treated (diet and sulfonilurea) ype 2 diabetic patients, group B, 310 insulin treated type 2 diabetic patients, ;roup C, 338 type 1 diabetic patients and group D, 1240 control subjects. the patients were matched for age, gender and diabetes duration. For all ;ubjects cholesterol, triglicerides and HDL cholesterol were determined and ?VRS was assessed for according to the European Coronary Chart (1994). E)LP was diagnosed if cholesterol > 200 mg/dl, triglicerides > 150 mg/dl, md HDLchol < 35 mg/dl. Results: the most significantly prevalent condition that was found was aypercholesterolemia: 75% in group B, 66% in group A, 57.3% in group ~" and D. Hypertrigliceridemia prevalence was also high. The isolated arevalence in group B was 51.8% and in group A 36.4% in both conditions. l'he CVRS was higher in group A and B vs. groups C and D (30.2%, 24.1%, 33.4%, 25.1% vs. 9%, 12.1%, 15.4%, 14.8%). In spite of the fact that mixed ~yperlipidaemia has a lower prevalence (but not significant) the CVRS is =omparable (27.4%, 31.4%) for groups B and A. The prevalence of isolated low HDLchol is reduced but CVRS is high in these patients. Conclusion: hypercholesterolemia, hypertrigliceridemia and mixed hyperlipidaemias are serious atherogenic risk factors in DM. VLDL SUBFRACTIONS (A-D) IN TYPE 2 DIABETES: THEIR SUSCEPTIBILITY TO OXIDATION AND LIPID COMPOSITION J. McEneny "1, M.M.J. O'Kane 2, C. McMaster3, D. McMaster4, C. Mercer4, E.R. Trimble 1, I.S. Young 1. The Departments of tClinical Biochemistr),;
~Child Health; eMedicine. The Queen ~" UniuersiO; Belfast: 2AItnageluin Hospital, Dert3, N Ireland, UK The aim of this study was to determine if the dyslipidaemia associated with type II diabetes caused alterations in fatty acid and lipid distribution within VLDL subfractions. Susceptibility to copper mediated oxidation and levels of preformed peroxide were also assessed. Fifteen patients with type 11 diabetes were matched for age and sex with 15 healthy controls Four subfractions of VLDL were isolated (A-D, with A being the largest and least dense subfraction) by rapid sequential ultracentrifugation. Lipid analysis of each subfraction included MUFAs, PUFAs, SFAs, cholesterol and triglyceride. Production of conjugated dienes was used an indicator of in vitro lipid oxidation. Preformed peroxides were measured using the FOX II assay. Results show that as subfractions become smaller and more dense (A---, D), the FA profile changes. Subfractions from the control group showed that MUFAs remained constant throughout the 4 subfractions, whilst PUFAs increased and SFAs decreased. Subfractions A ~ D; MUFAs 36.8 ---,35.5%: PUFAs 21.9" ---.26.3%: SFAs 41.6" - , 38.1%. Patient subfractions showed a decrease in MUFAs and an increase in PUFAs, whilst SFAs remained constant throughout all 4 subfractions. Subfractions A ~ D; MUFAs 34.8*--, 33.0%: PUFAs 22.8*---* 26.0%: SFAs 41.9 ~ 40.8%. When FA distribution was compared between the patient and control group, the patient group had lower levels of MUFAs in all 4 subfractions. Cholesterol was higher in patient subfractions A, B&C when compared with control, Sub A: 0.07 V's 0.03*, Sub B: 0.19" V's 0.I I, Sub C: 0.13" V's 0.07 mmol/l. Triglyceride was also higher in patient subfraction A, Sub A: 0.21" V's 0.17 mmol/I (*p < 0.05). Preformed peroxides were increased in the patient group in all 4 subfractions. Patients V's controls: Subfraction A; 15.17" V's 6.58 nmol/mg protein (p --- 0.002). Subfraction B; 13.78" V's 6.27 nmol/mg protein (p = 0.006). Subfraetion C; 23.29* V's 8.83 nmol/mg protein (p = 0.002). Subfraction D; 23.46* V's 8.92 nmol/mg protein (p = 0.004). Lag time results calculated from conjugated diene measurement showed that Subfractions A and D were more easily oxidised in the patient group; lag times for subfractions B and C were also shorter in the patient group although this did not reach
INFLUENCE OF POST-PRANDIAL PHASE ON LP(a) LEVELS D. Siepi, G. Lupattelli, C. Casciari, A.R. Roscini, M. Pirro, S. Marchesi, S. Pag]]-aricci, B. Palumbo, E. Mannarino. Dept. of Clinical and Sperimental
Medicine, Internal Medicine and Angiology, Uniuersity of Perugia, Italy Many studies have shown triglyceridemia and Lp(a) levels are negatively correlated, but results are devergent on Lp(a) modification after an oral fat tolerance test (OFTT). We determined Lp(a) levels and its isoform after OFTT in n. 50 post-menopausal women: 17 with primary hypercholesterolemia (HC), 16 with mixed hypercholesterolemia (MH) and 17 normolipemic (N). Blood sample were taken after 14 hours fast and 4, 6 and 8 hours after the OFTT contaning 65 gr/m 2 fat. Lp(a) was determined by ELISA and the $4, $3, $2, SI and B isoforms by Western Blot and immunoblotting. Subjects were divided into two groups on the basis of the isoform molecular weights: low (L) those with $2, Sl and B isoforms or high (H) $4, $3 and Null Type isoforms. Subjects with double band phenotype were classificated by the dominant isoform. Median Lp(a) values were as follows: 7.3 mg/dl in N subjects, 10.9 mg/dl in MH and 25.7 mg/dl in HC. The maximum reduction in Lp(a) levels was observed at the 6th hour in N subjects (5.8 mg/dl, p < 0.01) and in MH subjects (8.5 mg/dl, p < 0.01). and at the 4th hour in HC subjects (24.8 mg/dl, p < 0.001 ) and coincided in all subjects with the triglyceride peak. The post-prandial drop in Lp(a) levels was significantly higher (p < 0.05) in H subjects comparing with L subjects indipendently of triglyceride magnitudo. Post-prandial hypertriglyceridemia reduces Lp(a) levets particulary in the presence of high molecular weight isoforms while low molecular weight isoforms appear to be less susceptible. Consequently post-prandial hyperlipemia may be considered as atherogenic agent despite the drop in Lp(a) levels.
TRYGLICERIDE-RICH-LIPOPROTEINS AND NITRIC OXIDEDEPENDENT ENDOTHELIAL FUNCTION E Ricci, L. Vergnani, N. Manzoli, P. Donega, G. Zuliani, T. Malinski, R. Fellin. Institute of Internal Medicine, Unit;ersity of Ferrara, Ferrara,
Italy: Dept of Chemist~., Oakland Uniuersit); Rochester, Michigan, USA Recent epidemiological studies suggested that hypertriglyceridemia can be accepted as a risk factor for coronary heart disease (CHD), but the mechanism behind the role of triglycerides is not yet completely understood. It is well known that one of the main marker of the endothelial dysfunction present in subjects with high risk factor for CHD is a reduced endothelialdependent relaxation. The aim of the present study was to evaluate the relation between nitric oxide (NO) production and trygliceride-rich-lipoproteins (TRL) by exposing bovine aorta endothelial cells to increasing concentration of chylomicrons and VLDL. NO production has been determined by using a porphyrinic microsensor and placing the tip o f the microsensor on the surface ofa monolayer of endothelial cells. Chylomicrons and VLDLs were obtained from human plasma of hypertriglyceridemic patients with familial hyperchyIomicronemia by density gradient ultmcentrifugation. In the first step, the endothelial cells were exposed for one hour to increasing concentration o f c'hylomicrons and VLDL. In the second step we evaluated the effect of HDL and L-arginine pre-treatment in NO production in VLDL-treated cells. NO depletion was observed and significant (p < 0.005) only at chylomicron concentration above 500 mg/dL, where NO levels were decreased to 45% of the control. In VLDL-treated cells NO level was threefold lower at the concentration of 300 mg TG/dL. L-arginine and HDL supplementation restored the NO level at all VLDL concentrations even if HDL effect was more effective. These results suggest that hyperehylomicronemia may be involved in the reduced endothelial-dependent relaxation and may act decreasing NO production and altering the L-arginine-NO system.
71st EAS Congress and Satellite Symposia
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