Maximal lactate steady state declines during the aging process

Increased participation of aged individuals in athletics warrants basic research focused on delineating age-related changes in performance variables. On the basis of potential age-related declines in aerobic enzyme activities and a shift in the expression of myosin heavy chain (MHC) isoforms, we hypothesized that maximal lactate steady-state (MLSS) exercise intensity would be altered as a function of age. Three age groups [young athletes (YA), 25.9 ± 1.0 yr, middle-age athletes (MA), 43.2 ± 1.0 yr, and older athletes (OA), 64.6 ± 2.7 yr] of male, competitive cyclists and triathletes matched for training intensity and duration were studied. Subjects performed a maximal O2 consumption (V̇o2 max) test followed by a series of 30-min exercise trials to determine MLSS. A muscle biopsy of the vastus lateralis was procured on a separate visit. There were differences ( P < 0.05) in V̇o2 max among all age groups (YA = 67.7 ± 1.2 ml · kg-1 · min-1, MA = 56.0 ± 2.6 ml · kg-1 · min-1, OA = 47.0 ± 2.6 ml · kg-1 · min-1). When expressed as a percentage of V̇o2 max, there was also an age-related decrease ( P < 0.05) in the relative MLSS exercise intensity (YA = 80.8 ± 0.9%, MA = 76.1 ± 1.4%, OA = 69.9 ± 1.5%). There were no significant age-related changes in citrate synthase activity or MHC isoform profile. The hypothesis is supported as there is an age-related decline in MLSS exercise intensity in athletes matched for training intensity and duration. Although type I MHC isoform, combined with age, is helpful in predicting ( r = 0.76, P < 0.05) relative MLSS intensity, it does not explain the age-related decline in MLSS.

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Effects of aging and obesity on respiratory muscle phenotype in Zucker rats

Journal of Applied Physiology ◽

10.1152/jappl.1996.81.3.1347 ◽

1996 ◽

Vol 81 (3) ◽

pp. 1347-1354 ◽

Cited By ~ 22

Author(s):

S. K. Powers ◽

G. A. Farkas ◽

H. Demirel ◽

J. Coombes ◽

L. Fletcher ◽

...

Keyword(s):

Respiratory Muscle ◽

Citrate Synthase ◽

Work Of Breathing ◽

Age Groups ◽

Respiratory Muscles ◽

Oxidative Capacity ◽

Zucker Rats ◽

Type I ◽

Inspiratory Muscles ◽

Age Related

Because obesity results in an increased work of breathing, we tested the hypothesis that the oxidative properties and myosin heavy chain (MHC) isoform profiles in respiratory muscles would differ between lean and obese animals. Furthermore, we postulated that obesity-related changes in respiratory muscles would be independent of age. To test these hypothesis, samples of the costal diaphragm, crural diaphragm, and parasternal intercostal muscles were removed from three age groups (young, adult, and old) of obese and lean Zucker rats. Citrate synthase (CS) activity was measured as a marker of oxidative capacity, and MHC isoforms were identified with gel electrophoresis. Analysis revealed that CS activity was significantly higher in the crural and costal diaphragms and parasternal intercostal of obese animals compared with lean animals (P < 0.05); this obesity-related increased in CS activity was related independent of age. Furthermore, respiratory muscle percent type IIb MHC was lower and percent type I MHC isoforms were higher in obese animals compared with lean animals. These data support the notion that obesity results in a fast-to-slow shift in MHC phenotype and an increase in oxidative capacity in major inspiratory muscles. The shift in MHC isoforms in obese animals is also age related, whereas the obesity-mediated increase in oxidative capacity is relatively independent of age.

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Age-Related Changes in Molecular and Whole Muscle Function: Role of Fat Content?

Innovation in Aging ◽

10.1093/geroni/igaa057.463 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

pp. 141-141

Author(s):

Joseph Gordon III ◽

Nicholas Remillard ◽

Chad Straight ◽

Rajakumar Nagarajan ◽

Bruce Damon ◽

...

Keyword(s):

Older Adults ◽

Molecular Mechanisms ◽

Fat Content ◽

Fat Deposition ◽

Muscle Size ◽

Type I ◽

Contraction Velocity ◽

Age Related ◽

Whole Muscle ◽

Age Related Changes

Abstract Decreases in muscle size and function are a general consequence of old age; the precise mechanisms of these changes remain unclear. Recent studies suggest that fat deposition in muscle may also contribute to dysfunction in older adults. Fat content was quantified in the quadriceps, and its effects on function in healthy young (21-45 y) and older (65-75 y) men and women (n=44) of comparable physical activity were compared. A subset of the young matched with the older group for muscle fat content were also examined. Peak fat-free whole muscle cross-sectional area (mCSA; cm2), volume (MV; cm3), fat content (fat fraction, FF; %), specific torque (Nm/mCSA) and peak contraction velocity (Nm∙s-1) were determined using fat-water magnetic resonance imaging and dynamometry (0-300□∙s-1). To examine potential molecular mechanisms of muscle weakness, vastus lateralis biopsies were obtained (n=31) and cross-bridge kinetics of type I and II fibers were determined. FF was higher in older adults than young (8.4±1.2% (SE), 7.6±1.4; p=0.03), while mCSA (48.9±10.4 vs. 64.2±17.3), MV (1536±532 vs. 2112±708), specific torque (2.6±0.4 vs. 3.2±0.4), and peak voluntary contraction velocity (422±20 vs. 441±23) were lower in older than young (p<0.01). Type II fiber myosin attachment rate was slower and attachment time longer in older muscle (p<0.017), providing a potential mechanism for the slowing of peak contraction velocity with age. Notably, differences at the whole muscle and molecular levels remained for the subset of young and older groups matched for FF, suggesting that fat deposition in muscle does not exacerbate age-related changes in function.

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Age-related changes in renal and hepatic cellular mechanisms associated with variations in rat serum thyroid hormone levels

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00044.2008 ◽

2008 ◽

Vol 294 (6) ◽

pp. E1160-E1168 ◽

Cited By ~ 23

Author(s):

Elena Silvestri ◽

Assunta Lombardi ◽

Pieter de Lange ◽

Luigi Schiavo ◽

Antonia Lanni ◽

...

Keyword(s):

Thyroid Hormone ◽

Total Protein ◽

Protein Level ◽

Monocarboxylate Transporter ◽

Type I ◽

Peripheral Tissues ◽

Protein Levels ◽

Age Related ◽

Liver And Kidney ◽

Age Related Changes

Aging is associated with changes in thyroid gland physiology. Age-related changes in the contribution of peripheral tissues to thyroid hormone serum levels have yet to be systematically assessed. Here, we investigated age-related alterations in the contributions of the liver and kidney to thyroid hormone homeostasis using 6-, 12-, and 24-mo-old male Wistar rats. A significant and progressive decline in plasma thyroxine occurred with age, but triiodothyronine (T3) was decreased only at 24 mo. This was associated with an unchanged protein level of the thyroid hormone transporter monocarboxylate transporter 8 (MCT8) in the kidney and with a decreased MCT8 level in the liver at 24 mo. Hepatic type I deiodinase (D1) protein level and activity declined progressively with age. Renal D1 levels were decreased at both 12 and 24 mo but D1 activity was decreased only at 24 mo. In the liver, no changes occurred in thyroid hormone receptor (TR) TRα1, whereas a progressive increase in TRβ1 occurred at both mRNA and total protein levels. In the kidney, both TRα1 and TRβ1 mRNA and total protein levels were unchanged between 6 and 12 mo but increased at 24 mo. Interestingly, nuclear TRβ1 levels were decreased in both liver and kidney at 12 and 24 mo, whereas nuclear TRα1 levels were unchanged. Collectively, our data show differential age-related changes among hepatic and renal MCT8 and D1 and TR expressions, and they suggest that renal D1 activity is maintained with age to compensate for the decrease in hepatic T3 production.

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Age-related changes in molecular organization of type I collagen in tendon as probed by polarized SHG and Raman microspectroscopy

Scientific Reports ◽

10.1038/s41598-019-43636-2 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 7

Author(s):

Laurence Van Gulick ◽

Charles Saby ◽

Hamid Morjani ◽

Abdelilah Beljebbar

Keyword(s):

Type I Collagen ◽

Raman Microspectroscopy ◽

Molecular Organization ◽

Type I ◽

Age Related ◽

Age Related Changes

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Age-related changes in behavioural and emotional problems in Smith–Magenis syndrome measured with the Developmental Behavior Checklist

Journal of Intellectual Disabilities ◽

10.1177/1744629519901056 ◽

2020 ◽

pp. 174462951990105 ◽

Cited By ~ 1

Author(s):

Heidi Elisabeth Nag ◽

Terje Nærland

Keyword(s):

Age Groups ◽

Emotional Problems ◽

Chromosome 17 ◽

Adaptive Behaviour ◽

Genetic Syndrome ◽

Developmental Behavior ◽

Age Related ◽

Autism Symptomatology ◽

Behavioural And Emotional Problems ◽

Age Related Changes

Smith–Magenis syndrome (SMS) is a genetic syndrome most often caused by a deletion on chromosome 17 or more rarely by a mutation in the retinoic acid-induced 1 gene. The aim of this study was to investigate the Developmental Behavior Checklist (DBC) profile of persons with SMS and the associations between behavioural and emotional problems, age, gender, adaptive behaviour and autism symptomatology. Twenty-eight persons with SMS were represented by their parents in this study. DBC Total scores are reduced with age, but they still show a mean that is clearly above the cut-off of 46. The differences between the age groups <9 years and 9–17 years ( p = 0.024) and between the age groups <9 years and >18 years ( p = 0.007) are significant. We found a significant decrease in behavioural and emotional problems with age in SMS. We did not find a relationship between adapted behaviour and communication and behavioural and emotional problems.

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Age-Related Changes in Scleral Material Properties of the Monkey Eye

ASME 2008 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2008-192833 ◽

2008 ◽

Author(s):

Michaël J. A. Girard ◽

Jun-Kyo F. Suh ◽

Michael Bottlang ◽

Claude F. Burgoyne ◽

J. Crawford Downs

Keyword(s):

Intraocular Pressure ◽

Material Properties ◽

Lamina Cribrosa ◽

Collagen Fibers ◽

Visual Signals ◽

Type I ◽

Retinal Ganglion ◽

Age Related ◽

The Brain ◽

Age Related Changes

The sclera is the outer shell and principal load-bearing tissue of the eye, which consists primarily of avascular lamellae of collagen fibers. Ninety percent of the collagen fibers in the sclera are Type I, which provide the eye with necessary mechanical strength to sustain intraocular pressure (IOP). In the posterior sclera, there is a fenestrated canal, called the optic nerve head (ONH), through which the retinal ganglion cell axons pass transmitting visual signals from the retina to the brain. The opening of the ONH is structurally supported by a fenestrated connective tissue called the lamina cribrosa.

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Investigation of Age-Related Changes in the Skin Microbiota of Korean Women

Microorganisms ◽

10.3390/microorganisms8101581 ◽

2020 ◽

Vol 8 (10) ◽

pp. 1581

Author(s):

Minseok Kim ◽

Tansol Park ◽

Jung Im Yun ◽

Hye Won Lim ◽

Na Rae Han ◽

...

Keyword(s):

Age Groups ◽

Alpha Diversity ◽

Amplicon Sequencing ◽

Diversity Indices ◽

Rrna Gene ◽

Korean Women ◽

Skin Microbiota ◽

Microbial Distribution ◽

Age Related ◽

Age Related Changes

The microbiota of human skin is influenced by host and environmental factors. To determine if chronological age influences the composition of the skin microbiota on the forehead and hands, 73 Korean women were sorted into one of three age groups: (1) 10–29 years (n = 24), (2) 30–49 years (n = 21), and (3) 50–79 years (n = 28). From the 73 women, 146 skin samples (two skin sites per person) were collected. 16S rRNA gene amplicon sequencing was then conducted to analyze the skin microbiota. The overall microbial distribution varied on the forehead but was similar on the hands across the three age groups. In addition, the composition of the skin microbiota differed between the forehead and hands. Commensal microbiota, such as Streptococcus, Staphylococcus, Cutibacterium, and Corynebacterium, which contribute to maintaining skin health via dominant occupation, were affected by increasing age on forehead and hand skin. Alpha diversity indices increased significantly with age on forehead skin. This study indicates that older people may be more susceptible to pathogenic invasions due to an imbalanced skin microbiota resulting from age-related changes. The results of our study may help develop new strategies to rebalance skin microbiota shifted during aging.

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Age Related Changes in Weight of the Thymus Gland of Bangladeshi People

Bangladesh Journal of Anatomy ◽

10.3329/bja.v8i1.6101 ◽

1970 ◽

Vol 8 (1) ◽

pp. 10-12

Author(s):

Meherunnessa Begum ◽

Uttam Kumar Paul ◽

Md Jahangir Alam

Keyword(s):

Effect of aging on tracheal mucociliary clearance in beagle dogs

Journal of Applied Physiology ◽

10.1152/jappl.1987.62.3.1331 ◽

1987 ◽

Vol 62 (3) ◽

pp. 1331-1334 ◽

Cited By ~ 19

Author(s):

S. L. Whaley ◽

B. A. Muggenburg ◽

F. A. Seiler ◽

R. K. Wolff

Keyword(s):

Young Adult ◽

Gamma Camera ◽

Mucociliary Clearance ◽

Age Groups ◽

Beagle Dogs ◽

Velocity Measurements ◽

Middle Aged ◽

Age Related ◽

Age Related Changes ◽

Made In

Tracheal mucous velocity measurements were made in 24 beagle dogs in five age groups, using a gamma camera to detect movement of instilled 99mTc-macroaggregated albumin. Age groups were defined as immature (9–10 mo), young adult (2.8–3.0 yr), middle aged (6.7–6.9 yr), mature (9.6–9.8 yr), and aged dogs (13.6–16.2 yr). Mean velocities were 3.6 +/- 0.4 (SE) mm/min in the immature dogs, 9.7 +/- 0.6 mm/min in the young adults, 6.9 +/- 0.5 mm/min in the middle-aged dogs, 3.5 +/- 0.8 mm/min in the mature dogs, and 2.9 +/- 0.5 mm/min in the aged dogs. Tracheal mucous velocity was significantly (P less than 0.05) greater in the young adult and middle-aged groups compared with the immature, mature, and aged dogs. This pattern of age-related changes was noted to be similar to age-related changes described for certain pulmonary function measurements.

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