Limits...
Basal and insulin mediated VLDL-triglyceride kinetics in type 2 diabetic men.

Sørensen LP, Andersen IR, Søndergaard E, Gormsen LC, Schmitz O, Christiansen JS, Nielsen S - Diabetes (2010)

Bottom Line: VLDL-TG secretion was significantly greater in diabetic compared with healthy men (basal: 86.9 [31.0] vs. 61.9 [30.0] μmol/min, P = 0.03; clamp: 60.0 [26.2] vs. 34.2 [17.9] μmol · min⁻¹, P = 0.01).Basal VLDL-TG storage was similar, but significantly greater in abdominal compared with leg fat.During hyperinsulinemia VLDL-TG FA oxidation is significantly increased in proportion of EE in type 2 diabetic men.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology and Internal Medicine, University Hospital, Aarhus, Denmark.

ABSTRACT

Objective: Increased very-low-density lipoprotein triglycerides (VLDL-TG) concentration is a central feature of diabetic dyslipidemia. The objective was to compare basal and insulin mediated VLDL-TG kinetics, oxidation, and adipose tissue storage in type 2 diabetic and healthy (nondiabetic) men.

Research design and methods: Eleven type 2 diabetic and 11 healthy men, matched for BMI and age, were included. Ex vivo-labeled VLDL-TG tracers, blood and breath samples, fat biopsies, indirect calorimetry, and body composition measures were applied to determine VLDL-TG kinetics, VLDL-TG fatty acids (FA) oxidation, and storage in regional adipose tissue before and during a hyperinsulinemic euglycaemic clamp.

Results: VLDL-TG secretion was significantly greater in diabetic compared with healthy men (basal: 86.9 [31.0] vs. 61.9 [30.0] μmol/min, P = 0.03; clamp: 60.0 [26.2] vs. 34.2 [17.9] μmol · min⁻¹, P = 0.01). The insulin mediated suppression of VLDL-TG secretion was significant in both groups. VLDL-TG clearance was lower in diabetic men (basal: 84.6 [32.7] vs. 115.4 [44.3] ml · min⁻¹, P = 0.08; clamp: 76.3 [30.6] vs. 119.0 [50.2] ml · min⁻¹, P = 0.03). During hyperinsulinemia fractional VLDL-TG FA oxidation was comparable, but in percentage of energy expenditure (EE), significantly higher in diabetic men. Basal VLDL-TG storage was similar, but significantly greater in abdominal compared with leg fat.

Conclusions: Increased VLDL-TG in type 2 diabetic men is caused by greater VLDL-TG secretion and less so by lower VLDL-TG clearance. The ability of hyperinsulinemia to suppress VLDL-TG secretion appears preserved. During hyperinsulinemia VLDL-TG FA oxidation is significantly increased in proportion of EE in type 2 diabetic men. Greater basal abdominal VLDL-TG storage may help explain the accumulation of upper-body fat in insulin-resistant individuals.

Show MeSH

Related in: MedlinePlus

Breath 14CO2 SA steady state was reached in the clamp period, but not in the basal period (A). Therefore, only VLDL-TG FA oxidation data from the clamp period are illustrated and analyzed statistically. VLDL-TG FA oxidation expressed as fraction of secretion (B) and as oxidation rate (fractional oxidation × VLDL-TG secretion rate) (C). VLDL-TG FA oxidation as fraction of EE (D). Black circles and bars, healthy subjects; open (white) circles and bars, type 2 diabetic subjects. Data are mean ± SEM.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3012201&req=5

Figure 4: Breath 14CO2 SA steady state was reached in the clamp period, but not in the basal period (A). Therefore, only VLDL-TG FA oxidation data from the clamp period are illustrated and analyzed statistically. VLDL-TG FA oxidation expressed as fraction of secretion (B) and as oxidation rate (fractional oxidation × VLDL-TG secretion rate) (C). VLDL-TG FA oxidation as fraction of EE (D). Black circles and bars, healthy subjects; open (white) circles and bars, type 2 diabetic subjects. Data are mean ± SEM.

Mentions: Breath 14CO2 SA steady state was reached in the clamp period, but not in the basal period, allowing calculation of VLDL-TG FA oxidation only during the clamp. VLDL-TG FA oxidation during the clamp is depicted in Fig. 4B–D. The fraction of VLDL-TG secretion that was oxidized was comparable in diabetic and healthy men (44.8 [12.1] vs. 49.6 [10.4]%, ns). However, total VLDL-TG FA oxidation tended to be greater in diabetic compared with healthy men (27.7 [14.2] vs. 17.6 [12.2] μmol · min−1, P = 0.09). Expressed as a fraction of EE, the contribution from VLDL-TG FA to total substrate oxidation was significantly greater in diabetic men (16.7 [7.9] vs. 9.6 [6.3]%, P = 0.03).


Basal and insulin mediated VLDL-triglyceride kinetics in type 2 diabetic men.

Sørensen LP, Andersen IR, Søndergaard E, Gormsen LC, Schmitz O, Christiansen JS, Nielsen S - Diabetes (2010)

Breath 14CO2 SA steady state was reached in the clamp period, but not in the basal period (A). Therefore, only VLDL-TG FA oxidation data from the clamp period are illustrated and analyzed statistically. VLDL-TG FA oxidation expressed as fraction of secretion (B) and as oxidation rate (fractional oxidation × VLDL-TG secretion rate) (C). VLDL-TG FA oxidation as fraction of EE (D). Black circles and bars, healthy subjects; open (white) circles and bars, type 2 diabetic subjects. Data are mean ± SEM.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3012201&req=5

Figure 4: Breath 14CO2 SA steady state was reached in the clamp period, but not in the basal period (A). Therefore, only VLDL-TG FA oxidation data from the clamp period are illustrated and analyzed statistically. VLDL-TG FA oxidation expressed as fraction of secretion (B) and as oxidation rate (fractional oxidation × VLDL-TG secretion rate) (C). VLDL-TG FA oxidation as fraction of EE (D). Black circles and bars, healthy subjects; open (white) circles and bars, type 2 diabetic subjects. Data are mean ± SEM.
Mentions: Breath 14CO2 SA steady state was reached in the clamp period, but not in the basal period, allowing calculation of VLDL-TG FA oxidation only during the clamp. VLDL-TG FA oxidation during the clamp is depicted in Fig. 4B–D. The fraction of VLDL-TG secretion that was oxidized was comparable in diabetic and healthy men (44.8 [12.1] vs. 49.6 [10.4]%, ns). However, total VLDL-TG FA oxidation tended to be greater in diabetic compared with healthy men (27.7 [14.2] vs. 17.6 [12.2] μmol · min−1, P = 0.09). Expressed as a fraction of EE, the contribution from VLDL-TG FA to total substrate oxidation was significantly greater in diabetic men (16.7 [7.9] vs. 9.6 [6.3]%, P = 0.03).

Bottom Line: VLDL-TG secretion was significantly greater in diabetic compared with healthy men (basal: 86.9 [31.0] vs. 61.9 [30.0] μmol/min, P = 0.03; clamp: 60.0 [26.2] vs. 34.2 [17.9] μmol · min⁻¹, P = 0.01).Basal VLDL-TG storage was similar, but significantly greater in abdominal compared with leg fat.During hyperinsulinemia VLDL-TG FA oxidation is significantly increased in proportion of EE in type 2 diabetic men.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology and Internal Medicine, University Hospital, Aarhus, Denmark.

ABSTRACT

Objective: Increased very-low-density lipoprotein triglycerides (VLDL-TG) concentration is a central feature of diabetic dyslipidemia. The objective was to compare basal and insulin mediated VLDL-TG kinetics, oxidation, and adipose tissue storage in type 2 diabetic and healthy (nondiabetic) men.

Research design and methods: Eleven type 2 diabetic and 11 healthy men, matched for BMI and age, were included. Ex vivo-labeled VLDL-TG tracers, blood and breath samples, fat biopsies, indirect calorimetry, and body composition measures were applied to determine VLDL-TG kinetics, VLDL-TG fatty acids (FA) oxidation, and storage in regional adipose tissue before and during a hyperinsulinemic euglycaemic clamp.

Results: VLDL-TG secretion was significantly greater in diabetic compared with healthy men (basal: 86.9 [31.0] vs. 61.9 [30.0] μmol/min, P = 0.03; clamp: 60.0 [26.2] vs. 34.2 [17.9] μmol · min⁻¹, P = 0.01). The insulin mediated suppression of VLDL-TG secretion was significant in both groups. VLDL-TG clearance was lower in diabetic men (basal: 84.6 [32.7] vs. 115.4 [44.3] ml · min⁻¹, P = 0.08; clamp: 76.3 [30.6] vs. 119.0 [50.2] ml · min⁻¹, P = 0.03). During hyperinsulinemia fractional VLDL-TG FA oxidation was comparable, but in percentage of energy expenditure (EE), significantly higher in diabetic men. Basal VLDL-TG storage was similar, but significantly greater in abdominal compared with leg fat.

Conclusions: Increased VLDL-TG in type 2 diabetic men is caused by greater VLDL-TG secretion and less so by lower VLDL-TG clearance. The ability of hyperinsulinemia to suppress VLDL-TG secretion appears preserved. During hyperinsulinemia VLDL-TG FA oxidation is significantly increased in proportion of EE in type 2 diabetic men. Greater basal abdominal VLDL-TG storage may help explain the accumulation of upper-body fat in insulin-resistant individuals.

Show MeSH
Related in: MedlinePlus