Effects of aging on capillary geometry and hemodynamics in rat  spinotrapezius muscle

The effects of aging on muscle microvascular structure and function may play a key role in performance deficits and impairment of O2 exchange within skeletal muscle of senescent individuals. To determine the effects of aging on capillary geometry, red blood cell (RBC) hemodynamics, and hematocrit in a muscle of mixed fiber type, spinotrapezius muscles from Fischer 344 × Brown Norway hybrid rats aged 6–8 mo [young (Y); body mass 421 ± 10 g, n = 6] and 26–28 mo [old (O); 561 ± 12 g, n = 6] were observed by high-resolution transmission light microscopy under resting conditions. The percentage of RBC-perfused capillaries (Y: 78 ± 3%; O: 75 ± 2%) and degree of tortuosity and branching (Y: 13 ± 2%; O: 13 ± 2%, additional capillary length) were not different in O vs. Y muscles. Lineal density of RBC-perfused capillaries in O was significantly reduced (Y: 30.7 ± 1.8, O: 22.8 ± 3.1 capillaries/mm; P < 0.05). However, RBC-perfused capillaries from O rats ( n = 78) exhibited increased RBC velocity ( VRBC) (Y: 219 ± 12, O: 310 ± 14 μm/s; P < 0.05) and RBC flux ( FRBC) (Y: 27 ± 2, O: 41 ± 2 RBC/s; P < 0.05) vs. Y rats ( n = 66). Thus O2 delivery per unit of muscle was not different between groups (Y: 894 ± 111, O: 887 ± 118 RBC · s-1 · mm muscle-1). Capillary hematocrit was not different in Y vs. O rats (Y: 26 ± 1%, O: 28 ± 1%: P > 0.05). These data indicate that in resting spinotrapezius muscle, aging decreases the lineal density of RBC-perfused capillaries while increasing mean VRBC and FRBC within those capillaries. Whereas muscle conductive O2 delivery and capillary hematocrit were unchanged, elevated VRBC reduces capillary RBC transit time and may impair the diffusive transport of O2 from blood to myocyte particularly under exercise conditions.

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The Effects of Aging on Indices of Oxidative Stress and Apoptosis in the Female Fischer 344/Nnia X Brown Norway/BiNia Rat Heart

The Open Cardiovascular Medicine Journal ◽

10.2174/1874192401307010113 ◽

2013 ◽

Vol 7 (1) ◽

pp. 113-121 ◽

Cited By ~ 8

Author(s):

Jacqueline Fannin ◽

Kevin M. Rice ◽

Srininvas Thulluri ◽

Ravi Kumar Arvapalli ◽

Paulette Wehner ◽

...

Keyword(s):

Superoxide Anion ◽

Caspase 3 ◽

Nitrosative Stress ◽

Descriptive Study ◽

Female Rats ◽

Brown Norway ◽

Rodent Models ◽

Fischer 344 ◽

Stress Markers ◽

Effects Of Aging

Oxidative-nitrosative stress may play a role in age-associated cardiovascular disease as implied by recent studies.However, limited research has been conducted using aged female rodent models. In this study, we examined hearts obtained from 6-, 26-, and 30-month old female Fischer 344/Nnia x Brown Norway/BiNia (F344xBN) rats in order to examine how aging affects levels of cardiac oxidative-nitrosative stress and apoptosis. Oxidative (superoxide anion and 4-HNE) and nitrosative (protein nitrosylation) stress markers were increased 180 ± 17 %, 110 ± 3 %, and 14 ± 2 %, respectively in 30-month hearts compared to the hearts of 6-month female rats. Coincident with these changes in oxidative-nitrosative stress, aging was also found to be associated with increases in the number of Tdt-mediated dUTP nick labeling (TUNEL)-positive cardiomyocytes, alterations in the Bax/Bcl-2 ratio, and elevated cleavage of caspase-3. Regression analysis demonstrates significant correlation in the age-associated changes markers of oxidative–nitrosative stress with changes in apoptotic signaling. The findings from this descriptive study imply that age-associated increases in mitochondrial-mediated apoptosis may be associated with the increase in oxidative-nitrosative stress in the aging F344xBN female heart.

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Skeletal muscle IGF-binding protein-3 and -5 expressions are age, muscle, and load dependent

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00253.2002 ◽

2003 ◽

Vol 284 (2) ◽

pp. E340-E350 ◽

Cited By ~ 25

Author(s):

Espen E. Spangenburg ◽

Tsghe Abraha ◽

Tom E. Childs ◽

J. Scott Pattison ◽

Frank W. Booth

Keyword(s):

Mrna Expression ◽

Soleus Muscle ◽

Gastrocnemius Muscle ◽

Muscle Size ◽

Brown Norway ◽

Type I ◽

Fischer 344 ◽

Muscle Aging ◽

Muscle Groups ◽

Igfbp 3

The purpose of the current study was to examine IGFBP-3, -4, and -5 mRNA and protein expression levels as a function of muscle type, age, and regrowth from an immobilization-induced atrophy in Fischer 344 × Brown Norway rats. IGFBP-3 mRNA expression in the 4-mo-old animals was significantly higher in the red and white portions of the gastrocnemius muscle compared with the soleus muscle. However, there were no significant differences in IGFBP-3 mRNA expression among any of the muscle groups in the 30-mo-old animals. There were no significant differences in IGFBP-5 mRNA expression in any of the muscle groups, whereas in the 30-mo-old animals there was significantly less IGFBP-5 mRNA expression in the white gastrocnemius compared with the red gastrocnemius muscles. Although IGFBP-3 and -5 proteins were detected in the type I soleus muscle with Western blot analyses, no detection was observed in the type II red and white portions of the gastrocnemius muscle. Aging from adult (18 mo) to old animals (30 mo) was associated with decreases in IGFBP-3 mRNA and protein and IGFBP-5 protein only in the soleus muscle. After 10 days of recovery from 10 days of hindlimb immobilization, IGFBP-3 mRNA and protein increased in soleus muscles from young (4-mo) rats; however, only IGFBP-3 protein increased in the old (30-mo) rats. Whereas there were no changes in IGFBP-5 mRNA expression during recovery, IGFBP-5 protein in the 10-day-recovery soleus muscle did increase in the young, but not in the old, rats. Because one of the functions of IGFBPs is to modulate IGF-I action on muscle size and phenotype, it is hypothesized that IGFBP-3 and -5 proteins may have potential modulatory roles in type I fiber-dominated muscles, aging, and regrowth from atrophy.

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Effect of acute nutritional deprivation on diaphragm structure and function in adolescent rats

Journal of Applied Physiology ◽

10.1152/jappl.1992.73.3.974 ◽

1992 ◽

Vol 73 (3) ◽

pp. 974-978 ◽

Cited By ~ 14

Author(s):

M. I. Lewis ◽

G. C. Sieck

Keyword(s):

Body Mass ◽

Muscle Fiber ◽

Fiber Type ◽

Structure And Function ◽

Muscle Fiber Type ◽

Medial Gastrocnemius ◽

Diaphragm Muscle ◽

Nutritional Deprivation ◽

Ad Libitum ◽

And Function

The influence of 90 h of acute nutritional deprivation (ND; water ad libitum only) on in vitro contractile and fatigue properties, muscle fiber type proportions, and cross-sectional areas (CSA) of the adolescent rat diaphragm was determined. Diaphragm muscle properties in the ND rats were compared with those in control rats (CTL; food and water ad libitum). Acute ND resulted in a 32% reduction in body mass, whereas the body mass of CTL rats increased by 29%. Acute ND resulted in a significant reduction in the mass of the diaphragm (costal, 36%; crural, 43%), soleus (36%), and medial gastrocnemius (45%) muscles. Isometric twitch characteristics of the diaphragm muscle (contraction and half-relaxation times) were prolonged in the ND animals. Peak twitch and maximum tetanic forces were unaffected by ND. Fatigue resistance of the diaphragm muscle was improved in ND animals. Diaphragm muscle fiber type proportions were similar in ND and CTL groups. The CSA of type I and II diaphragm muscle fibers were reduced by 22 and 40%, respectively, in ND animals compared with CTL. We conclude that, whereas an identical protocol of acute ND had no significant effects on diaphragm muscle structure and function in adult rats, adolescent animals exhibit significantly less nutritional reserve. These differences may be due to curtailment of the rapid anabolic rate in growing animals.

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Interactive effects of denervation and malnutrition on diaphragm structure and function

Journal of Applied Physiology ◽

10.1152/jappl.1996.81.5.2165 ◽

1996 ◽

Vol 81 (5) ◽

pp. 2165-2172 ◽

Cited By ~ 27

Author(s):

Michael I. Lewis ◽

Thomas J. Lorusso ◽

Wen-Zhi Zhan ◽

Gary C. Sieck

Keyword(s):

Fiber Type ◽

Structure And Function ◽

Interactive Effects ◽

Diaphragm Muscle ◽

Fiber Types ◽

Specific Force ◽

Cross Sectional ◽

Total Cross Sectional Area ◽

Generating Capacity ◽

And Function

Lewis, Michael I., Thomas J. Lorusso, Wen-Zhi Zhan, and Gary C. Sieck. Interactive effects of denervation and malnutrition on diaphragm structure and function. J. Appl. Physiol. 81(5): 2165–2172, 1996.—The purpose of this study was to examine the interactive effects of unilateral denervation (DN) and prolonged malnutrition (MN) on the structure and function of the diaphragm muscle (Dia). Four groups of rats were studied: control (Con), MN, DN, and DN-MN. MN began 2 wk after DN and lasted 4 wk. In both the DN and DN-MN groups, the relative loss in Dia weight exceeded the relative change in body weight. Compared with the Con group, Dia specific force was reduced by ∼40% in both the DN and DN-MN groups but was unaffected in the MN group. Dia fatigue resistance improved in all experimental groups but to a greater extent in the DN and DN-MN groups. In both the DN and DN-MN groups, ∼50% of Dia fibers were classified as type IIc, whereas fiber type proportions did not change in the MN group. In the DN group, only type IIb/x fibers atrophied, whereas all fiber types atrophied in the MN and DN-MN groups. We conclude that in the DN-MN group the reduction in specific force combined with the reduction in total cross-sectional area of the muscle significantly curtails Dia force-generating capacity.

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Aging affects vascular structure and function in a limb-specific manner

Journal of Applied Physiology ◽

10.1152/japplphysiol.90612.2008 ◽

2008 ◽

Vol 105 (5) ◽

pp. 1661-1670 ◽

Cited By ~ 47

Author(s):

Steven K. Nishiyama ◽

D. Walter Wray ◽

Russell S. Richardson

Keyword(s):

Shear Rate ◽

Intima Media Thickness ◽

Structure And Function ◽

Vascular Pathology ◽

Ischemic Reperfusion ◽

Age Related ◽

Vessel Structure ◽

Healthy Young People ◽

Effects Of Aging ◽

And Function

The limb-specific effects of aging upon vessel structure and function are not well understood. Consequently, in 12 young (26 ± 2 yr) and 12 old (72 ± 1 yr) healthy subjects, we utilized ultrasound Doppler to evaluate intima-media thickness (IMT), ischemic reperfusion, and flow-mediated dilation (FMD) following (5 min) suprasystolic cuff occlusion in both the arm [brachial artery (BA)] and the leg [popliteal artery (PA)]. Structural measurements, whether normalized for vessel size or not, revealed a greater IMT in both the BA and PA with age (young: BA 0.028 ± 0.001 and PA 0.046 ± 0.003 cm, old: BA 0.039 ± 0.002 and PA 0.073 ± 0.005 cm; P < 0.05). Ischemic reperfusion revealed a similar pattern as IMT in terms of limb and age-related differences. There was an age-related attenuation in both BA FMD (old: 38% smaller BA FMD compared with young) and PA FMD (old: 71% smaller PA FMD compared with young). However, when this percent change was normalized for shear rate, only the PA FMD of the old group was still significantly attenuated (old: 41% smaller PA FMD/shear rate compared with young). Together, the finding of differential structural and functional parameters in the arms and legs of healthy young people, and the somewhat negative findings that are specific to the legs of otherwise healthy older people (greater IMT and attenuated FMD), support and may help to better understand the increased propensity to develop a vascular pathology in the legs with age.

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Effects of Aging on Nasal Structure and Function

American Journal of Rhinology ◽

10.2500/105065889782009714 ◽

1989 ◽

Vol 3 (2) ◽

pp. 59-62 ◽

Cited By ~ 4

Author(s):

Charles F. Koopmann

Keyword(s):

Structure And Function ◽

Functional Changes ◽

Effects Of Aging ◽

And Function

The aging nose undergoes structural and functional changes, which can cause alterations in olfaction, breathing, cosmesis, and nutrition, as well as exhibiting increased incidence of epistaxis and rhinitis. A review of these factors and suggestions for management is presented.

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