Written by Joyce Smith, BS. L-Carnitine, when given to cigarette smoke-exposed female mice prior to mating, and during gestation and lactation, significantly improved the brain markers of mitophagy and mitochondrial energy metabolism in the male and female offspring.
Smoking continues today among women of childbearing age and during pregnancy, and remains the leading cause of death worldwide 1. The well-documented adverse birth outcomes, such as type 2 diabetes mellitus, impaired renal function, and sudden infant death syndrome 2,3, are due to an increased maternal smoking risk and fetal exposure to intrauterine environmental stress 4. Previous studies by Chan et al 5,6 have shown that L-Carnitine decreases brain cell injury by increasing brain antioxidants and reducing cellular oxidative damage in pregnant mothers, thus prompting Y.L. Chan et al 7 to investigate whether L-Carnitine supplementation could boost the antioxidant capacity during infant early life and ameliorate the negative impact of maternal cigarette smoke exposure (SE) on the infant brain.
Prior to mating, and during gestation and lactation, a group of female Balb/c mice (8 weeks old) was exposed to cigarette smoke while a SHAM group had no smoke exposure. Half of the exposed group also received L-Carnitine (SELC) supplementation, 1.5 mM directly dissolved in drinking water. Offspring were sacrificed on day 1 or day 20 and brain analyses were done to investigate the effects of maternal L-Carnitine supplementation. Gender difference on the impacts of maternal SE on brain markers of autophagy, mitophagy, and mitochondrial energy metabolism in both male and female offspring as well as developmental changes of these markers from birth (Day 1) to maturity (13 weeks) were noted as follows:
- Male SE offspring (P<0.01) and their brain weight (P<0.05), were significantly smaller and male SECL significantly heavier (P<0.05) at birth than SHAM offspring (P<0.01), but at 20 days and 13 weeks weight differences were normalized by CL treatment (P<0.01), whereas female SE offspring remained small from birth to adulthood, with no affect on percentage brain weight, suggesting protection by L-carnitine (consistent with previous research) 5.
- By 13 weeks L-carnitine mitophagy markers of fusion had significantly decreased and fission significantly increased in the SELC offspring compared to both male and female SE offspring (P < 0.01) suggesting mitochondrial regeneration. (Mitophagy involves the removal of damaged mitochondria and the generation of new mitochondria, a process that recycles intact mitochondrial fragments to generate new healthy mitochondria through fission and fusion and maintains mitochondrial integrity 8,9. Fission fragments damaged mitochondria for removal while fusion regenerates new mitochondria; thus in the presence of stressors such as smoking, fusion is increased and acts as a protective mechanism to preserve and maintain energy synthesis 10).
- Female offspring were better protected from increased brain inflammation and oxidative stress while mitophagy and autophagy markers were increased and cell injury more pronounced in the male offspring. Researchers attribute the sex hormone estrogen with conferring neuroprotection 11.
As evidenced by the above results, L-carnitine supplementation during gestation and lactation may improve potential long term health outcomes in the offspring of cigarette-exposed mothers by replenishing infant brain mitophagy function.
Source: Chan, Yik Lung, Sonia Saad, Ibrahim Al-Odat, Brian G. Oliver, Carol Pollock, Nicole M. Jones, and Hui Chen. “Maternal L-carnitine supplementation improves brain health in offspring from cigarette smoke exposed mothers.” Frontiers in molecular neuroscience 10 (2017): 33.
© 2017 Chan, Saad, Al-Odat, Oliver, Pollock, Jones and Chen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY)..
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Posted May 11, 2018.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
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- Chan YL, Saad S, Al-Odat I, et al. Maternal L-carnitine supplementation improves brain health in offspring from cigarette smoke exposed mothers. Frontiers in molecular neuroscience. 2017;10:33.
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