Spermidine supplementation influences mitochondrial number and morphology in the heart of aged mice

AbstractChronic undernutrition contributes to the increase in frailty observed among elderly adults, which is a pressing issue in the sector of health care for older people worldwide. Autophagy, an intracellular recycling system, is closely associated with age-related pathologies. Therefore, decreased autophagy in aging could be involved in the disruption of energy homeostasis that occurs during undernutrition; however, the physiological mechanisms underlying this process remain unknown. Here, we showed that 70% daily food restriction (FR) induced fatal hypoglycemia in 23–26-month-old (aged) mice, which exhibited significantly lower hepatic autophagy than 9-week-old (young) mice. The liver expressions of Bcl-2, an autophagy-negative regulator, and Beclin1–Bcl-2 binding, were increased in aged mice compared with young mice. The autophagy inducer Tat-Beclin1 D11, not the mTOR inhibitor rapamycin, decreased the plasma levels of the glucogenic amino acid and restored the blood glucose levels in aged FR mice. Decreased liver gluconeogenesis, body temperature, physical activity, amino acid metabolism, and hepatic mitochondrial dynamics were observed in the aged FR mice. These changes were restored by treatment with hochuekkito that is a herbal formula containing several autophagy-activating ingredients. Our results indicate that Bcl-2 upregulation in the liver during the aging process disturbs autophagy activation, which increases the vulnerability to undernutrition. The promotion of liver autophagy may offer clinical therapeutic benefits to frail elderly patients.

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A 1-Month Ketogenic Diet Increased Mitochondrial Mass in Red Gastrocnemius Muscle, but not in the Brain or Liver of Middle-Aged Mice

Nutrients ◽

10.3390/nu13082533 ◽

2021 ◽

Vol 13 (8) ◽

pp. 2533

Author(s):

Zeyu Zhou ◽

Jocelyn Vidales ◽

José A González-Reyes ◽

Bradley Shibata ◽

Keith Baar ◽

...

Keyword(s):

Prefrontal Cortex ◽

Gastrocnemius Muscle ◽

Left Lobe ◽

Middle Aged ◽

Mitochondrial Content ◽

Mitochondrial Mass ◽

Aged Mice ◽

Fractional Area ◽

Ketogenic Diets ◽

The Impact

Alterations in markers of mitochondrial content with ketogenic diets (KD) have been reported in tissues of rodents, but morphological quantification of mitochondrial mass using transmission electron microscopy (TEM), the gold standard for mitochondrial quantification, is needed to further validate these findings and look at specific regions of interest within a tissue. In this study, red gastrocnemius muscle, the prefrontal cortex, the hippocampus, and the liver left lobe were used to investigate the impact of a 1-month KD on mitochondrial content in healthy middle-aged mice. The results showed that in red gastrocnemius muscle, the fractional area of both subsarcolemmal (SSM) and intermyofibrillar (IMM) mitochondria was increased, and this was driven by an increase in the number of mitochondria. Mitochondrial fractional area or number was not altered in the liver, prefrontal cortex, or hippocampus following 1 month of a KD. These results demonstrate tissue-specific changes in mitochondrial mass with a short-term KD and highlight the need to study different muscle groups or tissue regions with TEM to thoroughly determine the effects of a KD on mitochondrial mass.

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Melatonin insufficiency in the follicular fluid of aged mice; is it real?

Redox Biology ◽

10.1016/j.redox.2020.101829 ◽

2021 ◽

Vol 38 ◽

pp. 101829

Author(s):

David J. Kennaway

Keyword(s):

Follicular Fluid ◽

Aged Mice

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