scholarly journals Exercise-induced cardiac performance in autoimmune (Type 1) diabetes is associated with a decrease in myocardial diacylglycerol

2012 ◽  
Vol 113 (5) ◽  
pp. 817-826 ◽  
Author(s):  
Rajprasad Loganathan ◽  
Lesya Novikova ◽  
Igor G. Boulatnikov ◽  
Irina V. Smirnova
Keyword(s):  
Type 1 Diabetes ◽  
Exercise Training ◽  
Mitochondrial Fraction ◽  
Left Ventricular ◽  
Cardiac Performance ◽  
Diabetic Heart ◽  
Hemodynamic Assessment ◽  
Pkc Signaling ◽  
Exercise Induced

One of the fundamental biochemical defects underlying the complications of diabetic cardiovascular system is elevation of diacylglycerol (DAG) and its effects on protein kinase C (PKC) signaling. It has been noted that exercise training attenuates poor cardiac performance in Type 1 diabetes. However, the role of PKC signaling in exercise-induced alleviation of cardiac abnormalities in diabetes is not clear. We investigated the possibility that exercise training modulates PKC-βII signaling to elicit its beneficial effects on the diabetic heart. bio-breeding diabetic resistant rats, a model reminiscent of Type 1 diabetes in humans, were randomly assigned to four groups: 1) nonexercised nondiabetic (NN); 2) nonexercised diabetic (ND); 3) exercised nondiabetic; and 4) exercised diabetic. Treadmill training was initiated upon the onset of diabetes. At the end of 8 wk, left ventricular (LV) hemodynamic assessment revealed compromised function in ND compared with the NN group. LV myocardial histology revealed increased collagen deposition in ND compared with the NN group, while electron microscopy showed a reduction in the viable mitochondrial fraction. Although the PKC-βII levels and activity were unchanged in the diabetic heart, the DAG levels were increased. With exercise training, the deterioration of LV structure and function in diabetes was attenuated. Notably, improved cardiac performance in training was associated with a decrease in myocardial DAG levels in diabetes. Exercise-induced benefits on cardiac performance in diabetes may be mediated by prevention of an increase in myocardial DAG levels.

scholarly journals TLR4 regulates cardiac lipid accumulation and diabetic heart disease in the nonobese diabetic mouse model of type 1 diabetes

2012 ◽  
Vol 303 (6) ◽  
pp. H732-H742 ◽  
Author(s):  
Baojun Dong ◽  
Dake Qi ◽  
Long Yang ◽  
Yan Huang ◽  
Xiaoyan Xiao ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Heart Disease ◽  
Lipid Accumulation ◽  
Nod Mice ◽  
Left Ventricular ◽  
Diabetic Heart ◽  
Early Stages ◽  
Nonobese Diabetic ◽  
Diabetic Heart Disease

Toll-like receptor (TLR)4 regulates inflammation and metabolism and has been linked to the pathogenesis of heart disease. TLR4 is upregulated in diabetic cardiomyocytes, and we examined the role of TLR4 in modulating cardiac fatty acid (FA) metabolism and the pathogenesis of diabetic heart disease in nonobese diabetic (NOD) mice. Both wild-type (WT) NOD and TLR4-deficient NOD animals had increased plasma triglyceride levels after the onset of diabetes. However, by comparison, TLR4-deficient NOD mouse hearts had lower triglyceride accumulation in the early stages of diabetes, which was associated with a reduction in myeloid differentiation primary response gene (88) (MyD88), phosphorylation of p38 MAPK (phospho-p38), lipoprotein lipase (LPL), and JNK levels but increased phospho-AMP-activated protein kinase (AMPK). Oleic acid treatment in H9C2 cardiomyocytes also led to cellular lipid accumulation, which was attenuated by TLR4 small interfering RNA. TLR4 deficiency in the cells decreased FA-induced augmentation of MyD88, phospho-p38, and LPL, suggesting that TLR4 may modulate FA-induced lipid metabolism in cardiomyocytes. In addition, although cardiac function was impaired in both diabetic WT NOD and TLR4-deficient NOD animals compared with control nondiabetic mice, this deficit was less in the diabetic TLR4-deficient NOD mice, which had greater ejection fraction, greater fractional shortening, and increased left ventricular developed pressure in the early stages after the development of diabetes compared with their diabetic WT NOD counterparts. Thus, we conclude that TLR4 plays a role in regulating lipid accumulation in cardiac muscle after the onset of type 1 diabetes, which may contribute to cardiac dysfunction.

scholarly journals Exercise Training Improves but Does Not Normalize Left Ventricular Systolic and Diastolic Function in Adolescents With Type 1 Diabetes

Diabetes Care ◽  
2017 ◽  
Vol 40 (9) ◽  
pp. 1264-1272 ◽  
Author(s):  
Silmara Gusso ◽  
Teresa Pinto ◽  
James C. Baldi ◽  
José G.B. Derraik ◽  
Wayne S. Cutfield ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Exercise Training ◽  
Diastolic Function ◽  
Left Ventricular ◽  
Systolic And Diastolic Function

Cardiac responses to insulin-induced hypoglycemia in nondiabetic and intensively treated type 1 diabetic patients

2001 ◽  
Vol 281 (5) ◽  
pp. E1029-E1036 ◽  
Author(s):  
Raymond R. Russell ◽  
Deborah Chyun ◽  
Steven Song ◽  
Robert S. Sherwin ◽  
William V. Tamborlane ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Radionuclide Angiography ◽  
Left Ventricular ◽  
Cardiac Response ◽  
Left Ventricular Ejection ◽  
Diabetic Patients ◽  
Plasma Catecholamine ◽  
Ventricular Ejection Fraction ◽  
Type 1 Diabetic Patients

Insulin-induced hypoglycemia occurs commonly in intensively treated patients with type 1 diabetes, but the cardiovascular consequences of hypoglycemia in these patients are not known. We studied left ventricular systolic [left ventricular ejection fraction (LVEF)] and diastolic [peak filling rate (PFR)] function by equilibrium radionuclide angiography during insulin infusion (12 pmol · kg−1 · min−1) under either hypoglycemic (∼2.8 mmol/l) or euglycemic (∼5 mmol/l) conditions in intensively treated patients with type 1 diabetes and healthy nondiabetic subjects ( n = 9 for each). During hypoglycemic hyperinsulinemia, there were significant increases in LVEF (ΔLVEF = 11 ± 2%) and PFR [ΔPFR = 0.88 ± 0.18 end diastolic volume (EDV)/s] in diabetic subjects as well as in the nondiabetic group (ΔLVEF = 13 ± 2%; ΔPFR = 0.79 ± 0.17 EDV/s). The increases in LVEF and PFR were comparable overall but occurred earlier in the nondiabetic group. A blunted increase in plasma catecholamine, cortisol, and glucagon concentrations occurred in response to hypoglycemia in the diabetic subjects. During euglycemic hyperinsulinemia, LVEF also increased in both the diabetic (ΔLVEF = 7 ± 1%) and nondiabetic (ΔLVEF = 4 ± 2%) groups, but PFR increased only in the diabetic group. In the comparison of the responses to hypoglycemic and euglycemic hyperinsulinemia, only the nondiabetic group had greater augmentation of LVEF, PFR, and cardiac output in the hypoglycemic study ( P < 0.05 for each). Thus intensively treated type 1 diabetic patients demonstrate delayed augmentation of ventricular function during moderate insulin-induced hypoglycemia. Although diabetic subjects have a more pronounced cardiac response to hyperinsulinemia per se than nondiabetic subjects, their response to hypoglycemia is blunted.

scholarly journals The effects of exercise training versus intensive insulin treatment on skeletal muscle fibre content in type 1 diabetes mellitus rodents

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
David P. McBey ◽  
Michelle Dotzert ◽  
C. W. J. Melling
Keyword(s):  
Diabetes Mellitus ◽  
Skeletal Muscle ◽  
Type 1 Diabetes ◽  
Exercise Training ◽  
Muscle Fibre ◽  
Lipid Content ◽  
Fibre Type ◽  
Insulin Treatment ◽  
Type I

Abstract Background Intensive-insulin treatment (IIT) strategy for patients with type 1 diabetes mellitus (T1DM) has been associated with sedentary behaviour and the development of insulin resistance. Exercising patients with T1DM often utilize a conventional insulin treatment (CIT) strategy leading to increased insulin sensitivity through improved intramyocellular lipid (IMCL) content. It is unclear how these exercise-related metabolic adaptations in response to exercise training relate to individual fibre-type transitions, and whether these alterations are evident between different insulin strategies (CIT vs. IIT). Purpose: This study examined glycogen and fat content in skeletal muscle fibres of diabetic rats following exercise-training. Methods Male Sprague-Dawley rats were divided into four groups: Control-Sedentary, CIT- and IIT-treated diabetic sedentary, and CIT-exercised trained (aerobic/resistance; DARE). After 12 weeks, muscle-fibre lipids and glycogen were compared through immunohistochemical analysis. Results The primary findings were that both IIT and DARE led to significant increases in type I fibres when compared to CIT, while DARE led to significantly increased lipid content in type I fibres compared to IIT. Conclusions These findings indicate that alterations in lipid content with insulin treatment and DARE are primarily evident in type I fibres, suggesting that muscle lipotoxicity in type 1 diabetes is muscle fibre-type dependant.

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