Associations of Maternal Polyunsaturated Fatty Acids With Telomere Length in the Cord Blood and Placenta in Chinese Population

Fatty acids and telomere length

PURPOSE OF REVIEW

This narrative review includes the latest clinical and preclinical evidence on fatty acid exposure and telomere length, a widely accepted hallmark of aging.

RECENT FINDINGS

A large body of literature focused on n-3 (omega-3) polyunsaturated fatty acids (PUFAs). Observational studies reported beneficial associations with telomere length for self-reported consumption of n-3 PUFA-rich foods; for estimated intake of n-3 PUFAs; and for n-3 PUFAs blood-based biomarkers in most (but not all) studies involving lipidomics, a promising tool in the field. Benefits were also observed in preclinical studies using different mouse models. Regarding other lipids, inconsistent findings were observed for circulating linoleic acid, whereas inverse associations with telomere length were reported for the n-6/n-3 PUFA ratio. Finally, a study using Mendelian randomization reported that monounsaturated fatty acids and PUFAs have a positive effect on telomere length, whereas the opposite was observed for saturated fatty acids.

SUMMARY

Evidence supporting that n-3 PUFAs might have beneficial effects on maintaining telomere length reinforce the salutary effects of these dietary fats. Approach considering the n-6/n-3 PUFA ratio is discouraged because it is sustained in the incorrect assumption that all species from the n-6 and n-3 families are functionally equivalent.

Associations of Prenatal Mercury Exposure and PUFA with Telomere Length and mtDNA Copy Number in 7-Year-Old Children in the Seychelles Child Development Nutrition Cohort 2

BACKGROUND

Telomere length (TL) and mitochondrial DNA copy number (mtDNAcn) variations are linked to age-related diseases and are associated with environmental exposure and nutritional status. Limited data, however, exist on the associations with mercury exposure, particularly early in life.

OBJECTIVE

We examined the association between prenatal mercury (Hg) exposure and TL and mtDNAcn in 1,145 Seychelles children, characterized by a fish-rich diet.

METHODS

Total mercury (THg) was determined in maternal hair at delivery and cord blood. TL and mtDNAcn were determined relative to a single-copy hemoglobin beta gene in the saliva of 7-y-old children. Linear regression models assessed associations between THg and relative TL (rTL) and relative mtDNAcn (rmtDNAcn) while controlling for maternal and cord serum polyunsaturated fatty acid (PUFA) status and sociodemographic factors. Interactions between THg and child sex, PUFA, and telomerase genotypes were evaluated for rTL and rmtDNAcn.

RESULTS

Higher THg concentrations in maternal hair and cord blood were associated with longer rTL [β = 0.009 ; 95% confidence interval (CI): 0.002, 0.016 and β = 0.002 ; 95% CI: 0.001, 0.003, respectively], irrespective of sex, PUFA, or telomerase genotypes. Maternal serum n-6 PUFA and n-6/n-3 ratio were associated with shorter [β = - 0.24 ; 95% CI: - 0.33 , - 0.15 and β = - 0.032 ; 95% CI: - 0.048 , - 0.016 , respectively] and n - 3 PUFA with longer (β = 0.34 ; 95% CI: 0.032, 0.65) rTL. Cord blood n-6 PUFA was associated with longer (β = 0.15 ; 95% CI: 0.050, 0.26) rTL. Further analyses revealed linoleic acid in maternal blood and arachidonic acid in cord blood as the main drivers of the n-6 PUFA associations. No associations were observed for THg and PUFA with rmtDNAcn.

DISCUSSION

Our results indicate that prenatal THg exposure and PUFA status are associated with rTL later in childhood, although not consistently aligned with our initial hypothesis. Subsequent research is needed to confirm this finding, further evaluate the potential confounding of fish intake, and investigate the underlying molecular mechanisms to verify the use of rTL as a true biomarker of THg exposure. https://doi.org/10.1289/EHP14776.

Preterm Birth and Its Association with Maternal Diet, and Placental and Neonatal Telomere Length

Preterm birth (PTB), a multi-causal syndrome, is one of the global epidemics. Maternal nutrition, but also neonatal and placental telomere length (TL), are among the factors affecting PTB risk. However, the exact relationship between these factors and the PTB outcome, remains obscure. The aim of this review was to investigate the association between PTB, maternal nutrition, and placental-infant TL. Observational studies were sought with the keywords: maternal nutrition, placental TL, newborn, TL, and PTB. No studies were found that included all of the keywords simultaneously, and thus, the keywords were searched in dyads, to reach assumptive conclusions. The findings show that maternal nutrition affects PTB risk, through its influence on maternal TL. On the other hand, maternal TL independently affects PTB risk, and at the same time PTB is a major determinant of offspring TL regulation. The strength of the associations, and the extent of the influence from covariates, remains to be elucidated in future research. Furthermore, the question of whether maternal TL is simply a biomarker of maternal nutritional status and PTB risk, or a causative factor of PTB, to date, remains to be answered.

Dietary supplements and vascular function in hypertensive disorders of pregnancy

Hypertensive disorders of pregnancy are complications that can lead to maternal and infant mortality and morbidity. Hypertensive disorders of pregnancy are generally defined as hypertension and may be accompanied by other end organ damages including proteinuria, maternal organ disturbances including renal insufficiency, neurological complications, thrombocytopenia, impaired liver function, or uteroplacental dysfunction such as fetal growth restriction and stillbirth. Although the causes of these hypertensive disorders of pregnancy are multifactorial and elusive, they seem to share some common vascular-related mechanisms, including diseased spiral arteries, placental ischemia, and endothelial dysfunction. Recently, preeclampsia is being considered as a vascular disorder. Unfortunately, due to the complex etiology of preeclampsia and safety concerns on drug usage during pregnancy, there is still no effective pharmacological treatments available for preeclampsia yet. An emerging area of interest in this research field is the potential beneficial effects of dietary intervention on reducing the risk of preeclampsia. Recent studies have been focused on the association between deficiencies or excesses of some nutrients and complications during pregnancy, fetal growth and development, and later risk of cardiovascular and metabolic diseases in the offspring. In this review, we discuss the involvement of placental vascular dysfunction in preeclampsia. We summarize the current understanding of the association between abnormal placentation and preeclampsia in a vascular perspective. Finally, we evaluate several studied dietary supplementations to prevent and reduce the risk of preeclampsia, targeting placental vascular development and function, leading to improved pregnancy and postnatal outcomes.

Is depression the missing link between inflammatory mediators and cancer?

Patients with cancer are at greater risk of developing depression in comparison to the general population and this is associated with serious adverse effects, such as poorer quality of life, worse prognosis and higher mortality. Although the relationship between depression and cancer is now well established, a common underlying pathophysiological mechanism between the two conditions is yet to be elucidated. Existing theories of depression, based on monoamine neurotransmitter system dysfunction, are insufficient as explanations of the disorder. Recent advances have implicated neuroinflammatory mechanisms in the etiology of depression and it has been demonstrated that inflammation at a peripheral level may be mirrored centrally in astrocytes and microglia serving to promote chronic levels of inflammation in the brain. Three major routes to depression in cancer in which proinflammatory mediators are implicated, seem likely. Activation of the kynurenine pathway involving cytokines, increases tryptophan catabolism, resulting in diminished levels of serotonin which is widely acknowledged as being the hallmark of depression. It also results in neurotoxic effects on brain regions thought to be involved in the evolution of major depression. Proinflammatory mediators also play a crucial role in impairing regulatory glucocorticoid mediated feedback of the hypothalamic-pituitary-adrenal axis, which is activated by stress and considered to be involved in both depression and cancer. The third route is via the glutamatergic pathway, whereby glutamate excitotoxicity may lead to depression associated with cancer. A better understanding of the mechanisms underlying these dysregulated and other newly emerging pathways may provide a rationale for therapeutic targeting, serving to improve the care of cancer patients.

The relationship between n-3 polyunsaturated fatty acids and telomere: A review on proposed nutritional treatment against metabolic syndrome and potential signaling pathways

Metabolic syndrome (MetS), a cluster of metabolic abnormalities composed of central obesity, elevated blood pressure, glucose disturbances, hypercholesterolemia and dyslipidaemia, has increasingly become a public health problem in the 21st century worldwide. The dysfunction of telomeres, the repetitive DNA with highly conserved sequences (5'-TTAGGG-3'), is remarkably correlated with organismal aging, even suggesting a causal relationship with metabolic disorders. The health benefits of n-3 polyunsaturated fatty acids (PUFAs) in multiple disorders are associated with telomere length in evidence, which have recently drawn wide attention. However, functional targets and pathways for the associations of n-3 PUFAs and telomere with MetS remain scare. Few studies have summarized the role of n-3 PUFAs in DNA damage repair pathways, anti-inflammatory pathways, and redox balance, linking with telomere biology, and other potential telomere-related signaling pathways. This review aims to (i) elucidate how n-3 PUFAs ameliorate telomere attrition in the context of anti-oxidation and anti-inflammation; (ii) unravel the role of n-3 PUFAs in modulating telomere-related neuron dysfunction and regulating the neuro-endocrine-immunological network in MetS; (iii) epidemiologically implicate the associations of metabolic disorders and n-3 PUFAs with telomere length; and (iv) suggest promising biochemical approaches and advancing methodologies to overcome the inter-variation problem helpful for future research.

Effect of Omega-3 Fatty Acids on Telomeres-Are They the Elixir of Youth?

Telomeres are complexes consisting of tandem repeat DNA combined with associated proteins that play a key role in protecting the ends of chromosomes and maintaining genome stability. They are considered a biological clock, as they shorten in parallel with aging. Furthermore, short telomeres are associated with several age-related diseases. However, the variability in telomere shortening independent of chronological age suggests that it is a modifiable factor. In fact, it is regulated inter alia by genetic damage, cell division, aging, oxidative stress, and inflammation. A key question remains: how can we prevent accelerated telomere attrition and subsequent premature replicative senescence? A number of studies have explored the possible impact of omega-3 fatty acids on telomere shortening. This review summarizes published cross-sectional studies, randomized controlled trials, and rodent studies investigating the role of omega-3 fatty acids in telomere biology. It also covers a broad overview of the mechanism, currently favored in the field, that explains the impact of omega-3 fatty acids on telomeres—the food compound’s ability to modulate oxidative stress and inflammation. Although the results of the studies performed to date are not consistent, the vast majority indicate a beneficial effect of omega-3 fatty acids on telomere length.