Low intrinsic exercise capacity in rats predisposes to age-dependent cardiac remodeling independent of macrovascular function

Rebecca H. Ritchie, Chen Huei Leo, Chengxue Qin, Erin Stephenson, Marissa A. Bowden, Keith D. Buxton, Sarah J. Lessard, Donato A. Rivas, Lauren G. Koch, Steven L. Britton, John A. Hawley, Owen L. Woodman

Research output: Contribution to journalArticle

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Abstract

Rats selectively bred for low (LCR) or high (HCR) intrinsic running capacity simultaneously present with contrasting risk factors for cardiovascular and metabolic disease. However, the impact of these phenotypes on left ventricular (LV) morphology and microvascular function, and their progression with aging, remains unresolved. We tested the hypothesis that the LCR phenotype induces progressive age-dependent LV remodeling and impairments in microvascular function, glucose utilization, and β-adrenergic responsiveness, compared with HCR. Hearts and vessels isolated from female LCR (n = 22) or HCR (n = 26) were studied at 12 and 35 wk. Nonselected N:NIH founder rats (11 wk) were also investigated (n = 12). LCR had impaired glucose tolerance and elevated plasma insulin (but not glucose) and body-mass at 12 wk compared with HCR, with early LV remodeling. By 35 wk, LV prohypertrophic and glucose transporter GLUT4 gene expression were up- and downregulated, respectively. No differences in LV β-adrenoceptor expression or cAMP content between phenotypes were observed. Macrovascular endothelial function was predominantly nitric oxide (NO)-mediated in both phenotypes and remained intact in LCR for both age-groups. In contrast, mesenteric arteries microvascular endothelial function, which was impaired in LCR rats regardless of age. At 35 wk, endothelial-derived hyperpolarizing factor-mediated relaxation was impaired whereas the NO contribution to relaxation is intact. Furthermore, there was reduced β2-adrenoceptor responsiveness in both aorta and mesenteric LCR arteries. In conclusion, diminished intrinsic exercise capacity impairs systemic glucose tolerance and is accompanied by progressive development of LV remodeling. Impaired microvascular perfusion is a likely contributing factor to the cardiac phenotype.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume304
Issue number5
DOIs
StatePublished - Mar 11 2013

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Ventricular Remodeling
Exercise
Phenotype
Mesenteric Arteries
Glucose
Adrenergic Receptors
Nitric Oxide
Glucose Intolerance
Facilitative Glucose Transport Proteins
Metabolic Diseases
Running
Adrenergic Agents
Aorta
Cardiovascular Diseases
Down-Regulation
Age Groups
Perfusion
Insulin
Gene Expression

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Low intrinsic exercise capacity in rats predisposes to age-dependent cardiac remodeling independent of macrovascular function. / Ritchie, Rebecca H.; Leo, Chen Huei; Qin, Chengxue; Stephenson, Erin; Bowden, Marissa A.; Buxton, Keith D.; Lessard, Sarah J.; Rivas, Donato A.; Koch, Lauren G.; Britton, Steven L.; Hawley, John A.; Woodman, Owen L.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 304, No. 5, 11.03.2013.

Research output: Contribution to journalArticle

Ritchie, Rebecca H. ; Leo, Chen Huei ; Qin, Chengxue ; Stephenson, Erin ; Bowden, Marissa A. ; Buxton, Keith D. ; Lessard, Sarah J. ; Rivas, Donato A. ; Koch, Lauren G. ; Britton, Steven L. ; Hawley, John A. ; Woodman, Owen L. / Low intrinsic exercise capacity in rats predisposes to age-dependent cardiac remodeling independent of macrovascular function. In: American Journal of Physiology - Heart and Circulatory Physiology. 2013 ; Vol. 304, No. 5.
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abstract = "Rats selectively bred for low (LCR) or high (HCR) intrinsic running capacity simultaneously present with contrasting risk factors for cardiovascular and metabolic disease. However, the impact of these phenotypes on left ventricular (LV) morphology and microvascular function, and their progression with aging, remains unresolved. We tested the hypothesis that the LCR phenotype induces progressive age-dependent LV remodeling and impairments in microvascular function, glucose utilization, and β-adrenergic responsiveness, compared with HCR. Hearts and vessels isolated from female LCR (n = 22) or HCR (n = 26) were studied at 12 and 35 wk. Nonselected N:NIH founder rats (11 wk) were also investigated (n = 12). LCR had impaired glucose tolerance and elevated plasma insulin (but not glucose) and body-mass at 12 wk compared with HCR, with early LV remodeling. By 35 wk, LV prohypertrophic and glucose transporter GLUT4 gene expression were up- and downregulated, respectively. No differences in LV β-adrenoceptor expression or cAMP content between phenotypes were observed. Macrovascular endothelial function was predominantly nitric oxide (NO)-mediated in both phenotypes and remained intact in LCR for both age-groups. In contrast, mesenteric arteries microvascular endothelial function, which was impaired in LCR rats regardless of age. At 35 wk, endothelial-derived hyperpolarizing factor-mediated relaxation was impaired whereas the NO contribution to relaxation is intact. Furthermore, there was reduced β2-adrenoceptor responsiveness in both aorta and mesenteric LCR arteries. In conclusion, diminished intrinsic exercise capacity impairs systemic glucose tolerance and is accompanied by progressive development of LV remodeling. Impaired microvascular perfusion is a likely contributing factor to the cardiac phenotype.",
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AU - Ritchie, Rebecca H.

AU - Leo, Chen Huei

AU - Qin, Chengxue

AU - Stephenson, Erin

AU - Bowden, Marissa A.

AU - Buxton, Keith D.

AU - Lessard, Sarah J.

AU - Rivas, Donato A.

AU - Koch, Lauren G.

AU - Britton, Steven L.

AU - Hawley, John A.

AU - Woodman, Owen L.

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AB - Rats selectively bred for low (LCR) or high (HCR) intrinsic running capacity simultaneously present with contrasting risk factors for cardiovascular and metabolic disease. However, the impact of these phenotypes on left ventricular (LV) morphology and microvascular function, and their progression with aging, remains unresolved. We tested the hypothesis that the LCR phenotype induces progressive age-dependent LV remodeling and impairments in microvascular function, glucose utilization, and β-adrenergic responsiveness, compared with HCR. Hearts and vessels isolated from female LCR (n = 22) or HCR (n = 26) were studied at 12 and 35 wk. Nonselected N:NIH founder rats (11 wk) were also investigated (n = 12). LCR had impaired glucose tolerance and elevated plasma insulin (but not glucose) and body-mass at 12 wk compared with HCR, with early LV remodeling. By 35 wk, LV prohypertrophic and glucose transporter GLUT4 gene expression were up- and downregulated, respectively. No differences in LV β-adrenoceptor expression or cAMP content between phenotypes were observed. Macrovascular endothelial function was predominantly nitric oxide (NO)-mediated in both phenotypes and remained intact in LCR for both age-groups. In contrast, mesenteric arteries microvascular endothelial function, which was impaired in LCR rats regardless of age. At 35 wk, endothelial-derived hyperpolarizing factor-mediated relaxation was impaired whereas the NO contribution to relaxation is intact. Furthermore, there was reduced β2-adrenoceptor responsiveness in both aorta and mesenteric LCR arteries. In conclusion, diminished intrinsic exercise capacity impairs systemic glucose tolerance and is accompanied by progressive development of LV remodeling. Impaired microvascular perfusion is a likely contributing factor to the cardiac phenotype.

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