DHA-enriched fish oil upregulates cyclin-dependent kinase inhibitor 2A (P16INK) expression and downregulates telomerase activity without modulating effects of PPARγ Pro12Ala polymorphism in type 2 diabetic patients: A randomized, double-blind, placebo-controlled clinical trial

Impact of omega-3 fatty acids supplementation on the gene expression of peroxisome proliferator activated receptors-γ, α and fibroblast growth factor-21 serum levels in patients with various presentation of metabolic conditions: a GRADE assessed systematic review and dose-response meta-analysis of clinical trials

There is some debate about the effects of omega-3 fatty acids on the regulation of adipose tissue related genes. This systematic review and meta-analysis aimed to evaluate the effects of omega-3 fatty acids supplementation on the gene expression of peroxisome proliferator activated receptors (PPAR-α and PPAR-γ) and serum fibroblast growth factor-21 (FGF-21) levels in adults with different presentation of metabolic conditions. To identify eligible studies, a systematic search was conducted in the Cochrane Library of clinical trials, Medline, Scopus, ISI Web of Science, and Google Scholar up to April 2022. Eligibility criteria included a clinical trial design, omega-3 fatty acids supplementation in adults, and reporting of at least one of the study outcomes. Effect sizes were synthesized using either fixed or random methods based on the level of heterogeneity. Fifteen studies met the inclusion criteria. Omega-3 fatty acids supplementation significantly increased the PPAR-γ (10 studies) and PPAR-α (2 studies) gene expression compared to the control group (WMD: 0.24; 95% CI: 0.12, 0.35; p < 0.001 and 0.09; 95% CI: 0.04, 0.13; p < 0.001, respectively). Serum FGF-21 (8 studies) levels exhibited no significant change following omega-3 fatty acids supplementation (p = 0.542). However, a dose-response relationship emerged between the dose of omega-3 fatty acids and both PPAR-γ gene expression and serum FGF-21 levels. Overall, this study suggests that omega-3 fatty acids supplementation may have positive effects on the regulation of adipose tissue related genes in patients with various presentation of metabolic condition. Further research is needed to validate these findings and ascertain the effectiveness of this supplementation approach in this population.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?, CRD42022338344.

Protective Effects of Micronutrient Supplements, Phytochemicals and Phytochemical-Rich Beverages and Foods Against DNA Damage in Humans: A Systematic Review of Randomized Controlled Trials and Prospective Studies

Accumulation of deoxyribonucleic acid (DNA) damage diminishes cellular health, increases risk of developmental and degenerative diseases, and accelerates aging. Optimizing nutrient intake can minimize accrual of DNA damage. The objectives of this review are to: 1) assemble and systematically analyze high-level evidence for the effect of supplementation with micronutrients and phytochemicals on baseline levels of DNA damage in humans, and 2) use this knowledge to identify which of these essential micronutrients or nonessential phytochemicals promote DNA integrity in vivo in humans. We conducted systematic literature searches of the PubMed database to identify interventional, prospective, cross-sectional, or in vitro studies that explored the association between nutrients and established biomarkers of DNA damage associated with developmental and degenerative disease risk. Biomarkers included lymphocyte chromosome aberrations, lymphocyte and buccal cell micronuclei, DNA methylation, lymphocyte/leukocyte DNA strand breaks, DNA oxidation, telomere length, telomerase activity, and mitochondrial DNA mutations. Only randomized, controlled interventions and uncontrolled longitudinal intervention studies conducted in humans were selected for evaluation and data extraction. These studies were ranked for the quality of their study design. In all, 96 of the 124 articles identified reported studies that achieved a quality assessment score ≥ 5 (from a maximum score of 7) and were included in the final review. Based on these studies, nutrients associated with protective effects included vitamin A and its precursor β-carotene, vitamins C, E, B1, B12, folate, minerals selenium and zinc, and phytochemicals such as curcumin (with piperine), lycopene, and proanthocyanidins. These findings highlight the importance of nutrients involved in (i) DNA metabolism and repair (folate, vitamin B12, and zinc) and (ii) prevention of oxidative stress and inflammation (vitamins A, C, E, lycopene, curcumin, proanthocyanidins, selenium, and zinc). Supplementation with certain micronutrients and their combinations may reduce DNA damage and promote cellular health by improving the maintenance of genome integrity.

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.

Association of Polyunsaturated Fatty Acid Intake on Inflammatory Gene Expression and Multiple Sclerosis: A Systematic Review and Meta-Analysis

The health benefits of omega-3 fatty acid (FA) supplementation on inflammatory gene expression (IGE) and multiple sclerosis (MS) are becoming more evident. However, an overview of the results from randomized controlled trials is lacking. This study aimed to conduct a meta-analysis to evaluate the effect of omega-3 fatty acid intake on MS (based on the criteria of the Expanded Disability Status Scale (EDSS)) and inflammatory gene expression (IGE). A search was conducted of PubMed, EMBASE, and Web of Science for cohort studies published from the inception of the database up to May 2022 that assessed the associations of omega-3 polyunsaturated fatty acids (n-3 PUFAs), docosahexaenoic acid (DHA), α-linolenic acid (ALA), and eicosapentaenoic acid (EPA) with EDSS and inflammatory gene expression (peroxisome proliferator-activated receptor gamma (PPAR-γ), tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), and interleukin-8 (IL-8)) outcomes. For the highest vs. lowest comparison, the relative risk (RR) estimates with a 95% confidence interval (CI) were pooled using the random-effect model. In total, 13 cohort studies with 1353 participants were included in the meta-analysis during periods of 3 to 144 weeks. A significant inverse relationship was found between DHA and EDSS scores (RR: 1.05; 95% CI: 0.62, 1.48; p < 0.00001). Our results also showed that omega-3 FAs significantly upregulated the gene expression of PPAR-γ (RR: 0.95; 95% CI: 0.52, 1.38; p < 0.03) and downregulated the expression of TNF-α (RR: −0.15; 95% CI: −0.99, 0.70; p < 0.00001) and IL-1 (RR: −0.60; 95% CI: −1.02, −0.18; p < 0.003). There was no clear evidence of publication bias with Egger’s tests for inflammatory gene expression (p = 0.266). Moreover, n-3 PUFAs and EPA were not significantly associated with EDSS scores (p > 0.05). In this meta-analysis of cohort studies, blood omega-3 FA concentrations were inversely related to inflammatory gene expression (IGE) and EDSS score, which indicates that they may hold great potential markers for the diagnosis, prognosis, and management of MS. However, further clinical trials are required to confirm the potential effects of the omega-3 FAs on MS disease management.

Assessment of cell cycle regulators in human peripheral blood cells as markers of cellular senescence

Cellular senescence has gained increasing interest during recent years, particularly due to causal involvement in the aging process corroborated by multiple experimental findings. Indeed, cellular senescence considered to be one of the hallmarks of aging, is defined as a stable growth arrest predominantly mediated by cell cycle regulators p53, p21 and p16. Senescent cells have frequently been studied in the peripheral blood of humans due to its accessibility. This review summarizes ex vivo studies describing cell cycle regulators as markers of senescence in human peripheral blood cells, along with detection methodologies and associative studies examining demographic and clinical characteristics. The utility of techniques such as the quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), microarray, RNA sequencing and nCounter technologies for detection at the transcriptional level, along with Western blotting, enzyme-linked immunosorbent assay and flow cytometry at the translational level, will be brought up at salient points throughout this review. Notably, housekeeping genes or proteins serving as controls such as GAPDH and β-Actin, were found not to be stably expressed in some contexts. As such, optimization and validation of such genes during experimental design were recommended. In addition, the expression of cell cycle regulators was found to vary not only between different types of blood cells such as T cells and B cells but also between stages of cellular differentiation such as naïve T cells and highly differentiated T cells. On the other hand, the associations of the presence of cell cycle regulators with demographics (age, gender, ethnicity, and socioeconomic status), clinical characteristics (body mass index, specific diseases, disease-related parameters) and lifestyle vary in groups of participants. One envisions that increased understanding and insights into the assessment of cell cycle regulators as markers of senescence in human peripheral blood cells will help inform prognostication and clinical intervention in elderly individuals.

Effect of omega-3 fatty acid supplementation on telomere length and telomerase activity: A systematic review of clinical trials

Evidence suggests antioxidant and anti-inflammatory properties of omega-3 polyunsaturated fatty acids (n-3 PUFA). However, the effect of supplementation of this fatty acid profile on the telomere length and the telomerase enzyme activity was not revised yet. The PubMed and Embase® databases were used to search for clinical trials. A total of six clinical trials were revised. Omega-3 PUFA supplementation did not statistically affect telomere length in three out of three studies but affected telomerase activity in two out of four studies. The supplementation increased telomerase enzyme activity in subjects with first-episode schizophrenia. Besides, it decreased telomerase enzyme activity without modulating the effects of Pro12Ala polymorphism on the PPARγ gene in type 2 diabetes subjects. The methodological differences between the studies and the limited number of studies on the theme suggest that further studies are needed to elucidate the effects of n-3 PUFA supplementation on telomere length and telomerase enzyme activity in humans.

Targeting cellular senescence in cancer by plant secondary metabolites: A systematic review

Senescence suppresses tumor growth, while also developing a tumorigenic state in the nearby cells that is mediated by senescence-associated secretory phenotypes (SASPs). The dual function of cellular senescence stresses the need for identifying multi-targeted agents directed towards the promotion of cell senescence in cancer cells and suppression of the secretion of pro-tumorigenic signaling mediators in neighboring cells. Natural secondary metabolites have shown favorable anticancer responses in recent decades, as some have been found to target the senescence-associated mediators and pathways. Furthermore, phenolic compounds and polyphenols, terpenes and terpenoids, alkaloids, and sulfur-containing compounds have shown to be promising anticancer agents through the regulation of paracrine and autocrine pathways. Plant secondary metabolites are potential regulators of SASPs factors that suppress tumor growth through paracrine mediators, including growth factors, cytokines, extracellular matrix components/enzymes, and proteases. On the other hand, ataxia-telangiectasia mutated, ataxia-telangiectasia and Rad3-related, extracellular signal-regulated kinase/mitogen-activated protein kinase, phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin, nuclear factor-κB, Janus kinase/signal transducer and activator of transcription, and receptor tyrosine kinase-associated mediators are main targets of candidate phytochemicals in the autocrine senescence pathway. Such a regulatory role of phytochemicals on senescence-associated pathways are associated with cell cycle arrest and the attenuation of apoptotic/inflammatory/oxidative stress pathways. The current systematic review highlights the critical roles of natural secondary metabolites in the attenuation of autocrine and paracrine cellular senescence pathways, while also elucidating the chemopreventive and chemotherapeutic capabilities of these compounds. Additionally, we discuss current challenges, limitations, and future research indications.

The effects of resveratrol supplementation on PPARα, p16, p53, p21 gene expressions, and sCD163/sTWEAK ratio in patients with type 2 diabetes mellitus: A double-blind controlled randomized trial

The present study sought to evaluate the effect of resveratrol supplementation on mRNA expression levels of peroxisome proliferator-activated receptor alpha (PPARα), p53, p21, p16, and serum levels of cluster of differentiation 163 (CD163) to TNF-like weak inducer of apoptosis (TWEAK) ratio in patients with type 2 diabetes. In this double-blind randomized controlled trial, 71 patients were randomly assigned to receive either 1,000 mg of trans-resveratrol or placebo (methyl cellulose) for 8 weeks. Expression levels of genes of interest, and serum levels of sCD163 and sTWEAK were assessed at baseline and at the end of the study. Resveratrol supplementation significantly increased mRNA expression levels of p53 and p21 genes, compared with the placebo group (fold change of p53 = 1.29, p = .04; fold change of p21 = 1.46, p = .006). However, no significant effect on expression levels of PPARα and p16 genes was observed after supplementation. In addition, resveratrol significantly reduced serum levels of sCD163/sTWEAK ratio compared with the placebo group (p = .003). Resveratrol supplementation resulted in significant changes in p53 and p21 genes expression, while serum levels of sCD163/sTWEAK ratio also improved in the resveratrol group, without any significant change in adjusted sCD163 levels. More research is needed to confirm the beneficial effects of resveratrol for patients with diabetes.

Functional foods modulating inflammation and metabolism in chronic diseases: a systematic review

Chronic diseases are responsible for approximately 71% global deaths. These are characterized by chronic low-grade inflammation and metabolic alterations. "Functional foods" have been attributed with anti-inflammatory properties, demonstrated in cell lines and murine models; however, studies in humans are inconclusive. The purpose of this systematic review is to identify clinical trials that analyzed changes in inflammatory and metabolic mediators, in response to consumption of specific functional foods. A total of 3581 trials were screened and 88 were included for this review. Foods identified to regulate inflammation included cranberries, grapes, pomegranate, strawberries, wheat, whole grain products, low fat dairy products, yogurt, green tea, cardamom, turmeric, soy foods, almonds, chia seeds, flaxseed, pistachios, algae oil, flaxseed oil and grape seed oil. Clinical trials that focus on a dietary pattern rich in functional foods are necessary to explore if the additive effect of these foods lead to more clinically relevant outcomes.

Metabolomic and gene expression analysis to study the effects of dietary saturated and polyunsaturated fats

PURPOSE OF REVIEW

Give an update on recent dietary intervention studies that have used peripheral blood mononuclear cell gene expression analysis and/or metabolic profiling to understand how intake of polyunsaturated and saturated fat affects and biological pathways linked to cardiovascular disease.

RECENT FINDINGS

Several studies showed that intake of fish oil and vegetable oil, high in omega-3 fatty acids, reduced expression level of genes involved in inflammation. One intervention study showed that gene transcripts encoding genes involved inflammation and lipid metabolism increased after intake of polyunsaturated fat (mainly omega-6 fatty acids) compared to saturated fat. Additionally, using targeted metabolomics, the concentrations of atherogenic lipoprotein particles and several metabolites including palmitoylcarnitine, myristoylcarnitine, and kynurenine were reduced after intake of polyunsaturated fat compared to saturated fat, whereas acetate and acetoacetate were increased. The use of targeted metabolomics showed that overfeeding with polyunsaturated fat reduced the serum concentration of ceramides, dihydroceramides, glucosylceramides, and lactosylceramides, whereas overfeeding with saturated fat increased serum concentration of these metabolites.

SUMMARY

The use of gene expression profiling and metabolomics are promising tools to identify possible new biomarkers linking fat quality to cardiovascular disease risk.