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Impaired Coronary and Renal Vascular Function in Spontaneously Type 2 Diabetic Leptin-Deficient Mice.

Westergren HU, Grönros J, Heinonen SE, Miliotis T, Jennbacken K, Sabirsh A, Ericsson A, Jönsson-Rylander AC, Svedlund S, Gan LM - PLoS ONE (2015)

Bottom Line: Microvascular dysfunction affects both cardiac and renal function and is now recognized as a main driver of cardiovascular mortality and morbidity.Moreover, plasma L-arginine was lower in ob/ob mice, while asymmetric dimethylarginine was unaltered.In parallel to previously described metabolic disturbances, the leptin-deficient ob/ob mice also display cardiac and renal microvascular dysfunction.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.

ABSTRACT

Background: Type 2 diabetes is associated with macro- and microvascular complications in man. Microvascular dysfunction affects both cardiac and renal function and is now recognized as a main driver of cardiovascular mortality and morbidity. However, progression of microvascular dysfunction in experimental models is often obscured by macrovascular pathology and consequently demanding to study. The obese type 2 diabetic leptin-deficient (ob/ob) mouse lacks macrovascular complications, i.e. occlusive atherosclerotic disease, and may therefore be a potential model for microvascular dysfunction. The present study aimed to test the hypothesis that these mice with an insulin resistant phenotype might display microvascular dysfunction in both coronary and renal vascular beds.

Methods and results: In this study we used non-invasive Doppler ultrasound imaging to characterize microvascular dysfunction during the progression of diabetes in ob/ob mice. Impaired coronary flow velocity reserve was observed in the ob/ob mice at 16 and 21 weeks of age compared to lean controls. In addition, renal resistivity index as well as pulsatility index was higher in the ob/ob mice at 21 weeks compared to lean controls. Moreover, plasma L-arginine was lower in ob/ob mice, while asymmetric dimethylarginine was unaltered. Furthermore, a decrease in renal vascular density was observed in the ob/ob mice.

Conclusion: In parallel to previously described metabolic disturbances, the leptin-deficient ob/ob mice also display cardiac and renal microvascular dysfunction. This model may therefore be suitable for translational, mechanistic and interventional studies to improve the understanding of microvascular complications in type 2 diabetes.

No MeSH data available.


Related in: MedlinePlus

Representative color Doppler image for measurement of coronary flow Velocities.Typical recordings of resting and hyperaemic flow velocity measurement in the left coronary artery were performed with color Doppler ultrasound in lean and leptin-deficient (ob/ob) mice at 10, 16 and 21weeks of age. Hypereamic flow velocity was induced by intravenous infusion of adenosine (140 μg/kg/min). Coronary flow velocity reserve was calculated as the ratio of peak diastolic flow velocities (red line) before (resting) and during (hyperaemic) adenosine infusion. A: Resting coronay flow velocity in lean mice. B: Hyperaemic coronary flow velocity in lean mice. C: Resting coronary flow velocity in ob/ob mice. D: Hyperaemic coronary flow velocity in ob/ob mice.
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pone.0130648.g001: Representative color Doppler image for measurement of coronary flow Velocities.Typical recordings of resting and hyperaemic flow velocity measurement in the left coronary artery were performed with color Doppler ultrasound in lean and leptin-deficient (ob/ob) mice at 10, 16 and 21weeks of age. Hypereamic flow velocity was induced by intravenous infusion of adenosine (140 μg/kg/min). Coronary flow velocity reserve was calculated as the ratio of peak diastolic flow velocities (red line) before (resting) and during (hyperaemic) adenosine infusion. A: Resting coronay flow velocity in lean mice. B: Hyperaemic coronary flow velocity in lean mice. C: Resting coronary flow velocity in ob/ob mice. D: Hyperaemic coronary flow velocity in ob/ob mice.

Mentions: Transthoracic echocardiography was performed at 10, 16 and 21 weeks of age in all mice using a high-frequency ultrasound imaging system (Vevo 2100 VisualSonics, Inc, Toronto, Ontario, Canada) with a 40-MHz central frequency transducer. The protocol has been described previously [18]. Briefly, mice were initially anesthetized with 2.5% isoflurane and kept on low levels (1.0–1.5%) during ultrasound examination. The total time of anesthesia and protocol performance was approximately 25 minutes/mouse and projections were captured in the same order in all mice. Isoflurane is known to have vasodilating effect at levels of 2.5% and the low levels of 1.0–1.5% have been shown hemodynamically neutral and thus used during all ultrasound scanning [25]. Isoflurane is widely used for ultrasound examination due to its rapid onset and short half-life, which enables good control of anesthesia time and depth. These advantages are of particular importance in longitudinal studies to minimize stress levels in the mice. Moreover, our current CFVR protocol was validated during isoflurane anesthesia which has also been shown to give rise to stable heart rate [18,26]. Mice were kept on a ventilated and heated bench. The chest was shaved using an electrical razor and hair removal cream. A catheter (0.4 x 10mm, Becton Dickinson Infusion Therapy, Helsingborg, Sweden) was inserted into the tail vein for intravenous infusion of 0.25 mg/ml adenosine (140 μg/kg/min) (ITEM Development AB, Stocksund, Sweden) administration, using an infusion pump. Mean volume infused at 21 weeks of age were 17.4 μl/min and 28.3 μμl/min, for lean and ob/ob mice respectively. This dose of adenosine has been validated previously to induce hyperaemia without influencing systemic hemodynamics [18]. Resting and hyperaemic flow velocity in the left coronary artery (LCA) was measured in a modified long-axis view, recorded with a pulsed-wave Doppler in proximal LCA (Fig 1). Measurements of left ventricle dimensions were performed in standard B-mode images in short axis views at the papillary level.


Impaired Coronary and Renal Vascular Function in Spontaneously Type 2 Diabetic Leptin-Deficient Mice.

Westergren HU, Grönros J, Heinonen SE, Miliotis T, Jennbacken K, Sabirsh A, Ericsson A, Jönsson-Rylander AC, Svedlund S, Gan LM - PLoS ONE (2015)

Representative color Doppler image for measurement of coronary flow Velocities.Typical recordings of resting and hyperaemic flow velocity measurement in the left coronary artery were performed with color Doppler ultrasound in lean and leptin-deficient (ob/ob) mice at 10, 16 and 21weeks of age. Hypereamic flow velocity was induced by intravenous infusion of adenosine (140 μg/kg/min). Coronary flow velocity reserve was calculated as the ratio of peak diastolic flow velocities (red line) before (resting) and during (hyperaemic) adenosine infusion. A: Resting coronay flow velocity in lean mice. B: Hyperaemic coronary flow velocity in lean mice. C: Resting coronary flow velocity in ob/ob mice. D: Hyperaemic coronary flow velocity in ob/ob mice.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4476758&req=5

pone.0130648.g001: Representative color Doppler image for measurement of coronary flow Velocities.Typical recordings of resting and hyperaemic flow velocity measurement in the left coronary artery were performed with color Doppler ultrasound in lean and leptin-deficient (ob/ob) mice at 10, 16 and 21weeks of age. Hypereamic flow velocity was induced by intravenous infusion of adenosine (140 μg/kg/min). Coronary flow velocity reserve was calculated as the ratio of peak diastolic flow velocities (red line) before (resting) and during (hyperaemic) adenosine infusion. A: Resting coronay flow velocity in lean mice. B: Hyperaemic coronary flow velocity in lean mice. C: Resting coronary flow velocity in ob/ob mice. D: Hyperaemic coronary flow velocity in ob/ob mice.
Mentions: Transthoracic echocardiography was performed at 10, 16 and 21 weeks of age in all mice using a high-frequency ultrasound imaging system (Vevo 2100 VisualSonics, Inc, Toronto, Ontario, Canada) with a 40-MHz central frequency transducer. The protocol has been described previously [18]. Briefly, mice were initially anesthetized with 2.5% isoflurane and kept on low levels (1.0–1.5%) during ultrasound examination. The total time of anesthesia and protocol performance was approximately 25 minutes/mouse and projections were captured in the same order in all mice. Isoflurane is known to have vasodilating effect at levels of 2.5% and the low levels of 1.0–1.5% have been shown hemodynamically neutral and thus used during all ultrasound scanning [25]. Isoflurane is widely used for ultrasound examination due to its rapid onset and short half-life, which enables good control of anesthesia time and depth. These advantages are of particular importance in longitudinal studies to minimize stress levels in the mice. Moreover, our current CFVR protocol was validated during isoflurane anesthesia which has also been shown to give rise to stable heart rate [18,26]. Mice were kept on a ventilated and heated bench. The chest was shaved using an electrical razor and hair removal cream. A catheter (0.4 x 10mm, Becton Dickinson Infusion Therapy, Helsingborg, Sweden) was inserted into the tail vein for intravenous infusion of 0.25 mg/ml adenosine (140 μg/kg/min) (ITEM Development AB, Stocksund, Sweden) administration, using an infusion pump. Mean volume infused at 21 weeks of age were 17.4 μl/min and 28.3 μμl/min, for lean and ob/ob mice respectively. This dose of adenosine has been validated previously to induce hyperaemia without influencing systemic hemodynamics [18]. Resting and hyperaemic flow velocity in the left coronary artery (LCA) was measured in a modified long-axis view, recorded with a pulsed-wave Doppler in proximal LCA (Fig 1). Measurements of left ventricle dimensions were performed in standard B-mode images in short axis views at the papillary level.

Bottom Line: Microvascular dysfunction affects both cardiac and renal function and is now recognized as a main driver of cardiovascular mortality and morbidity.Moreover, plasma L-arginine was lower in ob/ob mice, while asymmetric dimethylarginine was unaltered.In parallel to previously described metabolic disturbances, the leptin-deficient ob/ob mice also display cardiac and renal microvascular dysfunction.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.

ABSTRACT

Background: Type 2 diabetes is associated with macro- and microvascular complications in man. Microvascular dysfunction affects both cardiac and renal function and is now recognized as a main driver of cardiovascular mortality and morbidity. However, progression of microvascular dysfunction in experimental models is often obscured by macrovascular pathology and consequently demanding to study. The obese type 2 diabetic leptin-deficient (ob/ob) mouse lacks macrovascular complications, i.e. occlusive atherosclerotic disease, and may therefore be a potential model for microvascular dysfunction. The present study aimed to test the hypothesis that these mice with an insulin resistant phenotype might display microvascular dysfunction in both coronary and renal vascular beds.

Methods and results: In this study we used non-invasive Doppler ultrasound imaging to characterize microvascular dysfunction during the progression of diabetes in ob/ob mice. Impaired coronary flow velocity reserve was observed in the ob/ob mice at 16 and 21 weeks of age compared to lean controls. In addition, renal resistivity index as well as pulsatility index was higher in the ob/ob mice at 21 weeks compared to lean controls. Moreover, plasma L-arginine was lower in ob/ob mice, while asymmetric dimethylarginine was unaltered. Furthermore, a decrease in renal vascular density was observed in the ob/ob mice.

Conclusion: In parallel to previously described metabolic disturbances, the leptin-deficient ob/ob mice also display cardiac and renal microvascular dysfunction. This model may therefore be suitable for translational, mechanistic and interventional studies to improve the understanding of microvascular complications in type 2 diabetes.

No MeSH data available.


Related in: MedlinePlus