Aspartame downregulates 3T3-L1 differentiation

Chronic Use of Artificial Sweeteners: Pros and Cons

Over the past few decades, the scientific community has been highly concerned about the obesity epidemic. Artificial sweeteners are compounds that mimic the sweet taste of sugar but have no calories or carbohydrates; hence, they are very popular among patients suffering from diabetes or obesity, aiming to achieve glycemic and/or weight control. There are four different types of sweeteners: artificial, natural, rare sugars, and polyols. Artificial and natural sweeteners are characterized as non-nutritional sweeteners (NNSs) since they do not contain calories. The extended use of sweeteners has been reported to have a favorable impact on body weight and glycemic control in patients with type 2 diabetes (T2DM) and on tooth decay prevention. However, there is concern regarding their side effects. Several studies have associated artificial sweeteners' consumption with the development of insulin resistance, nonalcoholic fatty liver disease (NAFLD), gastrointestinal symptoms, and certain types of cancer. The present review focuses on the description of different types of sweeteners and the benefits and possible deleterious effects of the chronic consumption of NNSs on children's health. Additionally, possible underlying mechanisms of the unfavorable effects of NNSs on human health are described.

Aspartame Safety as a Food Sweetener and Related Health Hazards

Aspartame is the methyl-ester of the aspartate-phenylalanine dipeptide. Over time, it has become a very popular artificial sweetener. However, since its approval by the main food safety agencies, several concerns have been raised related to neuropsychiatric effects and neurotoxicity due to its ability to activate glutamate receptors, as well as carcinogenic risks due to the increased production of reactive oxygen species. Within this review, we critically evaluate reports concerning the safety of aspartame. Some studies evidenced subtle mood and behavioral changes upon daily high-dose intake below the admitted limit. Epidemiology studies also evidenced associations between daily aspartame intake and a higher predisposition for malignant diseases, like non-Hodgkin lymphomas and multiple myelomas, particularly in males, but an association by chance still could not be excluded. While the debate over the carcinogenic risk of aspartame is ongoing, it is clear that its use may pose some dangers in peculiar cases, such as patients with seizures or other neurological diseases; it should be totally forbidden for patients with phenylketonuria, and reduced doses or complete avoidance are advisable during pregnancy. It would be also highly desirable for every product containing aspartame to clearly indicate on the label the exact amount of the substance and some risk warnings.

Effects of Nonnutritive Sweeteners on Body Composition Changes during Pubertal Growth

The effects of consuming specific types of nonnutritive sweeteners (NNSs) on adiposity changes in children have remained inconsistent. In this study, we aimed to investigate the effects of the intake of different kinds of NNSs on long-term adiposity changes during pubertal growth. Furthermore, we examined the above relationships among different sexes, pubertal stages, and levels of obesity. A total of 1893 6-15-year-old adults were recruited and followed-up every 3 months. The NNS-FFQ (Food Frequency Questionnaire) was conducted and urine samples were collected to investigate the effects of the selected sweeteners, which included acesulfame potassium, aspartame, sucralose, glycyrrhizin, steviol glycosides, and sorbitol. Multivariate linear mixed-effects models were used to examine the relationship between NNS intake and body composition. The consumption of aspartame, sucralose, glycyrrhizin, stevioside, and sorbitol was associated with decreased fat mass and increased fat-free mass. In the highest tertile group, the effects of NNS consumption on fat mass corresponded to values of -1.21 (95% CI: -2.04 to -0.38) for aspartame, -0.62 (95% CI: -1.42 to 0.19) for sucralose, -1.26 (95% CI: -2.05 to -0.47) for glycyrrhizin, -0.90 (95% CI: -2.28 to 0.48) for stevioside, and -0.87 (95% CI: -1.67 to -0.08) for sorbitol, while the effects on fat-free mass corresponded to values of 1.20 (95% CI: 0.36 to -0.38) for aspartame, 0.62 (95% CI: -0.19 to 1.43) for sucralose, 1.27 (95% CI: 0.48 to 2.06) for glycyrrhizin, 0.85 (95% CI: -0.53 to 2.23) for stevioside, and 0.87 (95% CI: 0.08 to 1.67) for sorbitol. Particularly, aspartame and sorbitol revealed a dose-responsiveness effect. The above finding was more prominent among girls than boys. Moreover, fat mass was significantly reduced in normal-weight children who consumed a moderate amount of aspartame and a large amount of glycyrrhizin and sorbitol compared with obese children. In conclusion, the NNS-specific and sex-specific effects of long-term NNS consumption revealed associations of decreasing fat mass and increasing fat-free mass for children undergoing pubertal growth.

Methionine sulfoxide suppresses adipogenic differentiation by regulating the mitogen-activated protein kinase signaling pathway

In this study, methionine sulfoxide (MetO) was identified as an active metabolite that suppresses adipogenesis after screening obese individuals versus the normal population. MetO suppressed the gene and protein expression of CCAAT/enhancer binding protein (C/EBP) α, adipocyte fatty acid binding protein 4 (FABP4), and the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) during human preadipocyte (HPA) differentiation. Adipogenesis decreased following MetO treatment; however, the preadipocyte number, proliferation, and apoptosis were unaffected. The activity of phosphorylated extracellular signal-related kinase (P-ERK) of the mitogen-activated protein kinase (MAPK) pathway was significantly inhibited in HPA after MetO treatment. Furthermore, treatment of preadipocytes with the selective P-ERK1/2 agonist Ro 67-7476 abolished the effect of MetO against adipogenesis suggesting that MetO function is dependent on the MAPK pathway. The mechanistic insights of adipogenesis suppression by MetO presented in this study shows its potential as an antiobesity drug.

Updated systematic assessment of human, animal and mechanistic evidence demonstrates lack of human carcinogenicity with consumption of aspartame

Aspartame has been studied extensively and evaluated for its safety in foods and beverages yet concerns for its potential carcinogenicity have persisted, driven primarily by animal studies conducted at the Ramazzini Institute (RI). To address this controversy, an updated systematic review of available human, animal, and mechanistic data was conducted leveraging critical assessment tools to consider the quality and reliability of data. The evidence base includes 12 animal studies and >40 epidemiological studies reviewed by the World Health Organization which collectively demonstrate a lack of carcinogenic effect. Assessment of >1360 mechanistic endpoints, including many guideline-based genotoxicity studies, demonstrate a lack of activity associated with endpoints grouped to key characteristics of carcinogens. Other non-specific mechanistic data (e.g., mixed findings of oxidative stress across study models, tissues, and species) do not provide evidence of a biologically plausible carcinogenic pathway associated with aspartame. Taken together, available evidence supports that aspartame consumption is not carcinogenic in humans and that the inconsistent findings of the RI studies may be explained by flaws in study design and conduct (despite additional analyses to address study limitations), as acknowledged by authoritative bodies.

Nonnutritive sweetener consumption during pregnancy, adiposity, and adipocyte differentiation in offspring: evidence from humans, mice, and cells

BACKGROUND

Obesity often originates in early life, and is linked to excess sugar intake. Nonnutritive sweeteners (NNS) are widely consumed as "healthier" alternatives to sugar, yet recent evidence suggests NNS may adversely influence weight gain and metabolic health. The impact of NNS during critical periods of early development has rarely been studied. We investigated the effect of prenatal NNS exposure on postnatal adiposity and adipocyte development.

METHODS

In the CHILD birth cohort (N = 2298), we assessed maternal NNS beverage intake during pregnancy and child body composition at 3 years, controlling for maternal BMI and other potential confounders. To investigate causal mechanisms, we fed NNS to pregnant C57BL6J mice at doses relevant to human consumption (42 mg/kg/day aspartame or 6.3 mg/kg/day sucralose), and assessed offspring until 12 weeks of age for: body weight, adiposity, adipose tissue morphology and gene expression, glucose and insulin tolerance. We also studied the effect of sucralose on lipid accumulation and gene expression in cultured 3T3-L1 pre-adipocyte cells.

RESULTS

In the CHILD cohort, children born to mothers who regularly consumed NNS beverages had elevated body mass index (mean z-score difference +0.23, 95% CI 0.05-0.42 for daily vs. no consumption, adjusted for maternal BMI). In mice, maternal NNS caused elevated body weight, adiposity, and insulin resistance in offspring, especially in males (e.g., 47% and 15% increase in body fat for aspartame and sucralose vs. controls, p < 0.001). In cultured adipocytes, sucralose exposure at early stages of differentiation caused increased lipid accumulation and expression of adipocyte differentiation genes (e.g., C/EBP-α, FABP4, and FASN). These genes were also upregulated in adipose tissue of male mouse offspring born to sucralose-fed dams.

CONCLUSION

By triangulating evidence from humans, mice, and cultured adipocytes, this study provides new evidence that maternal NNS consumption during pregnancy may program obesity risk in offspring through effects on adiposity and adipocyte differentiation.

Noncaloric Sweeteners in Children: A Controversial Theme

Noncaloric sweeteners (NCS) are food additives used to provide sweetness without adding calories. Their consumption has become more widespread around the world in all age groups, including children. The aim of this study is to show the state of the art about the intake of noncaloric sweeteners in children, as well as their benefits and consumption risk. Scientific searchers were used (PUBMED, Scopus, and Scielo) to analyze articles that included keywords (noncaloric sweeteners/saccharin/cyclamate/acesulfame potassium/aspartame/sucralose/stevia/children) in English, Spanish, and Portuguese. Authors conclude that it is imperative that health professionals judiciously and individually evaluate the overall benefits and risks of NCS use in consumers before recommending their use. Different subgroups of the population incorporate products containing NCS in their diet with different objectives, which should be considered when recommending a diet plan for the consumer. In childhood, in earlier age groups, this type of additives should be used as a dietary alternative when other forms of prevention in obesity are not sufficient.

Effect of lncRNA HOXA11-AS1 on adipocyte differentiation in human adipose-derived stem cells

AIMS

To determine the role of lncRNA HOXA11-AS1 on adipocyte differentiation.

METHODS

Human adipose-derived stem cells (hADSCs) were isolated from adipose tissues of patients and cultured in vitro, followed by knockdown of HOXA11-AS1. Then, adipocyte differentiation and expression of adipogenic-related genes (CEBP-α, DGAT2, CIDEC, and perilipin) were measured by RT-qPCR and Western blot.

RESULTS

We demonstrated that knockdown of HOXA11-AS1 inhibited adipocyte differentiation, leading to suppression of adipogenic-related gene (CEBP-α, DGAT2, CIDEC, and perilipin) transcription, as well as decreased lipid accumulation in hADSCs. In addition, lncRNA HOXA11-AS1 was highly expressed in obese patients and significantly increased during the process of adipocyte differentiation.

CONCLUSION

The results provide new insight into the molecular mechanism by which lncRNA HOXA11-AS1 is involved in adipogenesis and may have implications for the treatment of obesity and associated disorders.

Renal-protective and ameliorating impacts of omega-3 fatty acids against aspartame damaged MDCK cells

Aspartame is widely used artificial sweeteners as food additives. Several researchers have pointed that the controversial report on the use of aspartame over more than decades. Omega-3 fatty acids are essential and unsaturated fatty acids, and it plays a remarkable role in vision, intelligence, neural development, and metabolism of neurotransmitters. Therefore, the present study was aimed to investigate the effect of omega-3 fatty acids on aspartame treated renal cells. Experimental groups were divided into three such as sham control, aspartame treated, and aspartame with omega-3 fatty acids. Cell viability was determined by sulforhodamine-b assay and flow cytometric analysis. The experimental results showed that the aspartame induced altered cell viability were reduced following treatment of aspartame with omega-3 fatty acids. Altered cell morphology was recovered by omega-3 fatty acids. DNA damage appeared in the highest concentration of aspartame used in this study. DNA damage characteristics such as comet tail and tiny head sections did not appear in the omega-3 fatty acids treated cells. Several microvilli and vesicular structures were found in aspartame treated cells. Altered morphology such as rounding, microvilli, and formation of dome-like structures did not appear in the omega-3 fatty acids with aspartame treated cells. Caspase-3 mRNA and protein expression were increased in aspartame treated cells, and these levels were reduced following omega-3 fatty acids treatment. Taking all these data together, it is suggested that the omega-3 fatty acids may be a therapeutic agent to reduce the aspartame induced biochemical and morphological alterations in normal renal cells. © 2017 BioFactors, 43(6):847-857, 2017.

A study on effect of curcumin on anticerebral aneurysm in the male albino rats

INTRODUCTION

This study investigated the curcumin effect on the cerebral aneurysm. Apoptosis is known to play a fundamental role in the pathogenesis of a cerebral aneurysm. Therefore, we investigated the effect of curcumin on apoptosis of smooth muscle cells of a cerebral aneurysm-induced male albino rats.

METHODS

In this study, the cerebral aneurysm has been induced in the male albino rats by the CaCl₂ administration. After cerebral aneurysm induction, smooth muscle cells were isolated. Cells were treated with curcumin (25 & 50 mg/kg bwt) for 48 hr.

RESULTS

Curcumin reduced altered mitochondrial morphology significantly, evidenced through fluorescence and confocal study. Curcumin treatment reduced the expression of p53, caspase-3, and bax/bxl-2 ratio significantly. Curcumin treatment also reversed the cellular architecture of smooth muscle cell wall significantly. Fluorescence and the confocal study confirmed the reduction in apoptosis in a cerebral aneurysm-induced smooth muscle cells of male albino rats.

CONCLUSION

Taking all these data together, it may suggest that the curcumin could significantly reduce the CaCl₂-induced cerebral aneurysm through the inhibition of cell apoptosis in the cells.

Epimedium koreanum Nakai and its main constituent icariin suppress lipid accumulation during adipocyte differentiation of 3T3-L1 preadipocytes

Obesity is associated with a number of metabolic abnormalities such as type 2 diabetes and has become a major health problem worldwide. In the present study, we investigated the effects of Epimedium koreanum Nakai (Herba Epimedii, HE) and its main constituent icariin on the adipocyte differentiation in 3T3-L1 preadipocytes. HE extract and icariin significantly reduced lipid accumulation and suppressed the expressions of PPARγ, C/EBPα, and SREBP-1c in 3T3-L1 adipocytes. They also inhibited fatty acid synthase (FAS), acyl-Co A synthase (ACS1), and perilipin. Moreover, HE extract and icariin markedly increased the phosphorylation of AMPK. These results indicated that HE extract and icariin can inhibit the adipocyte differentiation through downregulation of the adipogenic transcription factors, suggesting that HE containing icariin may be used as a potential therapeutic agent in the treatment and prevention of obesity.

In Vitro Selective Anti-Proliferative Effect of Zinc Oxide Nanoparticles Against Co-Cultured C2C12 Myoblastoma Cancer and 3T3-L1 Normal Cells

The zinc oxide (ZnO) nanoparticle has been widely used in biomedical applications and cancer therapy and has been reported to induce a selective cytotoxic effect on cancer cell proliferation. The present study investigated the cytotoxicity of ZnO nanoparticles against co-cultured C2C12 myoblastoma cancer cells and 3T3-L1 adipocytes. Our results showed that the ZnO nanoparticles could be cytotoxic to C2C12 myoblastoma cancer cells than 3T3-L1 cells. The messenger RNA (mRNA) expressions of p53 and bax were significantly increased 114.3 and 118.2 % in the C2C12 cells, whereas 42.5 and 40 % were increased in 3T3-L1 cells, respectively. The mRNA expression of bcl-2 was reduced 38.2 and 28.5 % in the C2C12 and 3T3-L1 cells, respectively, whereas the mRNA expression of caspase-3 was increased 80.7 and 51.6 % in the C2C12 and 3T3-L1 cells, respectively. The protein expressions of p53, bax, and caspase-3 were significantly increased 40, 81.8, and 80 % in C2C12 cells, whereas 20.3, 28.2, and 37.9 % were increased in 3T3-L1 cells, respectively. The mRNA expression of bcl-2 was significantly reduced 32.2 and 22.7 % in C2C12 and 3T3-L1 cells, respectively. Caspase-3 enzyme activity and reactive oxygen species (ROS) were increased in co-cultured C2C12 cells compared to 3T3-L1 cells. Taking all these data together, it may suggest that ZnO nanoparticles severely induce apoptosis in C2C12 myoblastoma cancer cells than 3T3-L1 cells.

Investigation of role of aspartame on apoptosis process in HeLa cells -->

Aspartame is an artificial sweetener used as an alternate for sugar in several foods and beverages. The study reports that consumption of aspartame containing product could lead to cancer. However, the effect of aspartame on apoptosis process in cancer is not yet understood clearly. HeLa cells were exposed to different concentrations (0.01-0.05 mg/ml) of aspartame for 48 h. Cytotoxicity of aspartame on cancer cells was determined by SRB assay. The result indicates no significant changes on cell viability. Aspartame suppresses apoptosis process in cancer cells by down-regulation of mRNA expression of tumor suppressor gene p53, and pro-apoptotic gene bax. It up-regulates anti-apoptotic gene bcl-2 mRNA expression. In addition, Ki 67 and PCNA mRNA, and protein expressions were determined. Taking all these together, we conclude that aspartame may be a potent substance to slow-down the apoptosis process in HeLa cells. Further works are ongoing to understand the biochemical and molecular mechanism of aspartame in cancer cells.

ZnO Nanoparticles Upregulates Adipocyte Differentiation in 3T3-L1 Cells

The present study was aimed to investigate the effect of zinc oxide (ZnO) nanoparticles on 3T3-L1 cell differentiation, by quantitating peroxisome proliferators-activated receptor γ (PPARγ), CCAAT/enhancer binding protein α (C/EBPα), fatty acid binding protein 4 (FABP4), sterol regulatory element-binding transcription factor 1 (SREBP1), and serine-threonine kinase cyclin-dependent kinase 4 (cdk4), which are critical for adipogenesis. 3T3-L1 preadipocyte cells were cultured and differentiated with the standard differentiation medium. Sulforhodamine B (SRB) assay determined 3T3-L1 cell viability. ZnO nanoparticles increased the lipid accumulation in differentiated adipocytes as evidenced by Oil Red O staining. The quantitative PCR (qPCR) analysis showed that the PPARγ, FABP4, C/EBPα, and SREBP1 messenger RNA (mRNA) expression was significantly increased in the ZnO nanoparticle-treated 3T3-L1 adipocytes. Western blot analysis showed increased PPARγ, FABP4, C/EBPα, and SREBP1 protein expression compared to their respective controls. Also, the immunofluorescence study showed the increased cdk4 and PPARγ expression in the nanoparticle-treated cells. Taking all these data together, it is concluded that ZnO nanoparticles may be a potent substance to alter 3T3-L1 preadipocyte differentiation and adipogenesis.

Cytotoxic effects of aspartame on human cervical carcinoma cells

Aspartame is used as an artificial sweetener in more than 6000 food varieties. The present study aims to determine the effects of aspartame at various concentrations on the cell viability, morphology, ROS level and DNA of human cervical carcinoma cells over two time periods of exposure. The effects of aspartame on HeLa cell viability were investigated using the sulphorhodamine-B assay (SRB assay) and flow cytometry. Alkaline comet assay was carried out to determine the possible DNA damage induced by aspartame. Mitochondria-derived reactive oxygen species (ROS) were determined using 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). Fluorescence microscopy was used to determine the presence of apoptotic and necrotic cells following aspartame treatment. Cell viability was significantly altered following a higher concentration of aspartame exposure. Mitochondria-derived ROS increased at higher concentrations of aspartame exposure. Exposure to 10 mM and 20 mM of aspartame induced DNA fragmentation. Apoptotic and necrotic bodies were found in the range of 1-20 mM aspartame exposure. Exposure to high concentrations of aspartame may alter cell viability and morphology, and it may induce ROS generation and DNA damage in cervical carcinoma cells.

A Study on Neuroprotective Effects of Curcumin on the Diabetic Rat Brain

The present study was aimed to study the neuroprotective therapeutic effect of curcumin on the male albino rat brain. Subarachnoid hemorrhage leads to severe mortality rate and morbidity, and oxidative stress is a crucial factor in subarachnoid hemorrhage. Therefore, we investigated the effect of curcumin on oxidative stress and glutamate and glutamate transporter-1 on a subarachnoid hemorrhage-induced male albino rats. The curcumin commonly used for the treatment and saline used for the control. Curcumin (10 mg/kg bwt) dissolved in saline and administered orally to the rats for one week. Glutamate, glutamate transporter-1, malondialdehyde (MDA), superoxide dismutase (SOD), catalase, glutathione reductase and lactate dehydrogenase (LDH) activities were determined. Glutamate level was lower in the curcumin-treated rats compared to their respective controls. Glutamate transporter-1 did not alter in the curcumin-treated rats compared to their controls. Glutamate transporter-1 protein expression is significantly reduced in the curcumin-treated rats. MDA levels decreased 18 and 29 % in the hippocampus and the cortex region respectively. SOD (17% and 32%), and catalase (19% and 24%) activities were increased in the curcumin-treated hippocampus and the cortex region respectively. Glutathione reductase (13% and 19%) and LDH (21% and 30%) activities were increased in the treated hippocampus and the cortex region respectively. The mRNA expression of NK-kB and TLR4 was significantly reduced following curcumin treatment. Taking all these data together, the curcumin found to be effective against oxidative stress and glutamate neurotoxicity in the male albino rats.