Insight into the mechanism of aspartame-induced toxicity in male reproductive system following long-term consumption in mice model

Daytime aspartame intake results in larger influences on body weight, serum corticosterone level, serum/cerebral cytokines levels and depressive-like behaviors in mice than nighttime intake

Aspartame (APM) is one of the most widely used artificial sweeteners worldwide. Studies have revealed that consuming APM may negatively affect the body, causing oxidative stress damage to multiple organs and leading to various neurophysiological symptoms. However, it's still unclear if consuming APM and one's daily biological rhythm have an interactive effect on health. In this study, healthy adult C57BL/6 mice were randomly divided into four groups: Control group (CON), oral gavage sham group (OGS), daytime APM intragastric group (DAI) and nighttime APM intragastric group (NAI). DAI and NAI groups were given 80 mg/kg body weight daily for 4 weeks. We found that DAI and NAI groups had significantly increased mean body weight, higher serum corticosterone levels, up-regulated pro-inflammatory responses in serum and brain, and exacerbated depressive-like behaviors than the CON and the two APM intake groups. Moreover, all these changes induced by APM intake were more significant in the DAI group than in the NAI group. The present study, for the first time, revealed that the intake of APM and daily biological rhythm have an interactive effect on health. This suggests that more attention should be paid to the timing of APM intake in human beings, and this study also provides an intriguing clue to the circadian rhythms of experimental animals that researchers should consider more when conducting animal experiments.

The effect of aspartame on accelerating caspase-dependent apoptosis of pancreatic islet via ZIPK/STAT3/caspase 3 signaling pathway

Aspartame (ASP) as an important sugar substitute is widely used in pharmaceutical and food processing. Here, we compared the effects of ASP and sucrose on mice pancreatic islet cells in vivo and observed that ASP with the condition of high concentration and long-term exposure (HASP) could cause insulin secretion (500 mg/kg for 1 month). Next, we conducted iTRAQ mass spectrometry to profile the global phosphoproteome and found that phosphorylation of zipper-interacting protein kinase (ZIPK) in murine pancreatic islet tissues were induced at Thr197, Thr242, Thr282, and Ser328 by high-sucrose (HS) treatment, but only induced at Thr197 and Ser328 by HASP treatment. Simultaneously, phosphorylation of STAT3 could be induced at Tyr705 and Ser727 by HS but not by HASP. Furthermore, presence of activated STAT3 accompanied with autophagy was observed in HS treatment. In turn, the inactivation of STAT3 as well as enhanced expression of caspase 3 was observed in HASP treatment. We generated Thr242APro and Thr282Pro on ZIPK using CRISPR-Cas9 in β-TC3 cells and found the weakened interaction with STAT3 as well as the reduced phosphorylation of STAT3 even under HS stimulation. Finally, we observed that ankyrin repeat domain containing 11 (ANKRD11) could interact with ZIPK and play an inhibitory role in the phosphorylation of Thr242APro and Thr282Pro of ZIPK. However, HASP can induce the retention of ANKRD11 in the cytoplasm by phenylpyruvic acid (the metabolite of ASP). Taken together, this study determined that ASP with high concentration and long-term exposure could lead to caspase-dependent apoptosis of pancreatic islet cells through ANKRD11/ZIPK/STAT3 inhibition. Our results give evidence of adverse effects of aspartame on islet cells in some extreme conditions, which might help people to reconsider the biosafety of non-nutritive sweeteners.

The impact of non-caloric artificial sweetener aspartame on female reproductive system in mice model

BACKGROUND

Artificial sweeteners, used as sugar substitutes have found their ways into almost all the food items due to the notion that they are non-caloric. Aspartame is used in numerous food products throughout the world. The primary users of aspartame include diabetics and calorie conscious people who intend to limit their calorie intake.

METHODS

Female Swiss albino mice were divided into three groups (12 mice each) for the duration of 30 and 60 days consecutively. The treatment groups received 40 mg/kg b. w. aspartame orally. Hormone assays using ELISA and tissue histopathology have been performed along with the fertility assay to access the treatment outcomeon the fertility of treated mice in comparison to controls.

RESULTS

Present study reports that female mice treated with aspartame for 30 and 60 days showed significant reduction in body weight, relative organ weight of (liver and kidney) and gonadosomatic index. These changes were more significantly recorded in 60 days treatment group. Aspartame treated animals for 30 and 60 days showed duration-dependent decrease gonandotropins (follicle stimulating hormone and luteinizing hormone), and steroids (estradiol and progesterone). Moreover, severe histopathological changes, reduction in number of growing follicles, degenerative changes in follicular structure, corona radiata and zonagranulosa were also observed. Besides, histomorphological changes were also observed in the uterine structure including atrophic uterine endometrial glands, contracted endometrial lining, disruption of the endometrial structure and the shapes of blood vessels were also altered.

CONCLUSION

Non-nutritive artificial sweeteners including aspartame negatively impact the function of ovaries and feedback mechanism of reproductive hormones by affecting the hypothalamic-pituitary-gonadal axis. In light of present findings the aspartame negatively impacted the reproductive system of female mice. More studies are required to identify the molecular mechanism and the pathways involved.

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.

Long-term intake of aspartame-induced cardiovascular toxicity is reflected in altered histochemical parameters, evokes oxidative stress, and trigger P53-dependent apoptosis in a mouse model

Aspartame (ASP) is probably the best known artificial sugar substitute that is used widely in food. Many experimental studies have reported the toxicity of long-term administration of ASP in various organ tissues. However, there is little evidence available about the nature and mechanisms of the adverse effects of long-term consumption of ASP on the cardiovascular system. This study was conducted to evaluate the possible effects of ASP on heart tissue. For this study 36 mature male mice were divided into one control group and three groups which received respectively 40 mg/kg, 80 mg/kg and 160 mg/kg ASP orally, for 90 days. ASP at the doses of 80 and 160 mg/kg increased the serum content of malondialdehyde (MDA), but decreased serum nitric oxide (NO), creatine kinase (CK) and CK-MB, as well as blood superoxide dismutase (SOD) levels. Serum level of total anti-oxidant capacity (TAC) in blood was also reduced in serum at the dose of 80 mg/kg. Histochemical staining, including Periodic acid-Schiff, Masson's trichrome and Verhoeff-van Gieson staining, indicated that ASP at doses of 80 and 160 mg/kg reduced glycogen deposition and decreased the number of collagen and elastic fibres in the cardiac tissue. The cardiac expression of pro-apoptotic genes, including P53, Bax, Bcl-2 and Caspase-3, was modulated at the dose of 160 mg/kg. Moreover, transcription of Caspase-3 was up-regulated at the dose of 80 mg/kg. In conclusion, long-term consumption of ASP any higher than the acceptable daily intake (40 mg/kg) appears to act by promoting oxidative stress, has the potential to alter both histopathological and biochemical parameters, and induces P53-dependent apoptosis in cardiac tissue.

Repro-protective role of royal jelly in phenylhydrazine-induced hemolytic anemia in male mice: Histopathological, embryological, and biochemical evidence

To estimate the repro-protective effect of royal jelly (RJ) on phenylhydrazine (PHZ)-induced anemia's detrimental effects, 24 mature mice were divided into control group (0.10 mL normal saline; intra-peritoneally), RJ group (100 mg/kg/day; orally), experimental anemia (EA) group that received only PHZ (6 mg/100 g/48 h; intra-peritoneally), and RJ + EA (according to the previous prescription) group. After 35 days, testicular histoarchitecture, RNA damage in germinal cells, sperm characteristics, testicular total anti-oxidant capacity and malondialdehyde as well as serum testosterone levels, pre-implantation embryo development and cyclin D1 and c-myc mRNA levels at two-cell, morula and blastocyst stages were analyzed. Spermatogenesis indices were ameliorated following RJ co-administration. Moreover, RJ co-treatment reduced germinal cells RNA damage, improved sperm characteristics, boosted pre-implantation embryo development and restored androgenesis, and oxidant/anti-oxidant status. Co-administration of RJ also decreased mRNA levels of cyclin D1 and up-regulated those of c-myc in two-cell embryos, morulas and blastocysts. The findings suggest that RJ can play a repro-protective role in PHZ-induced anemia in mice through anti-oxidant defense system reinforcement and androgenesis restoration as well as cyclin D1 and c-myc expressions regulation.

Consumption of Sugar-Sweetened or Artificially Sweetened Beverages and Semen Quality in Young Men: A Cross-Sectional Study

BACKGROUND

Existing literature suggests that frequent consumption of sugar-sweetened drinks may be associated with lower semen quality. Studies performed in mice suggest a dose-response relationship between intake of saccharin or aspartame, two artificial sweeteners, and sperm and testis function.

METHODS

A cross-sectional study based on data from The Fetal Programming of Semen Quality (FEPOS) Cohort, including 1047 young men (mean age = 19 years) was performed. Each male participant completed an online questionnaire on health, health behavior and diet, and provided a semen sample. The associations between consumption of sugar-sweetened or artificially sweetened beverages (moderate ≥ 3 days/week; infrequent < 3 days/week) and semen quality were analyzed using a multivariable, negative, binomial regression model.

RESULTS

Sugar-sweetened or artificially sweetened beverage consumption was not strongly associated with either semen volume, sperm concentration, total sperm count or total motility in young men. The proportion of morphologically normal sperm was 11% lower (0.89 (95% CI 0.76, 1.04)) for moderate (≥3 days/week) consumption of artificially sweetened beverages relative to infrequent (<3 days/week).

CONCLUSION

Consumption of sugar-sweetened or artificially sweetened beverages, at the levels present in this study had limited effect on the measured markers of semen quality in young men.

Evaluation of Some Male and Female Rats’ Reproductive Hormones Following Administration of Aspartame With or Without Vitamin C or E

Aspartame (ASP) is a sugar substitute. Its use rose because it has been demonstrated to have deleterious effects after being metabolized. In the presence of antioxidant vitamins C or E, the effects of ASP on reproductive hormones of adult male and female Albino Wister rats were investigated. A total of eighty male and female rats were used in this study. The rats were divided into four groups: group 1, received no treatment; group 2, received ASP at 40 mg/kg BW; group 3, received ASP at 40 mg/kg BW with vitamin C at 150 mg/kg BW; and group 4, received ASP at 40 mg/kg BW and vitamin E at 100 mg/kg BW. All treatments were given orally by gavage needle once daily for consecutive 90 days. The levels of estradiol (E2), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone hormone (TH) were measured after 90 days in blood plasma. In comparison with the control group, ASP treatment resulted in lower levels of E2, FSH, and LH in male and female rats. When the antioxidants vitamin C or E was given, the effects of ASP were reversed, and the levels of E2, LH, and FSH were increased. The testosterone hormone was likewise significantly increased by ASP, but testosterone hormone concentrations were decreased by vitamin C or E treatments. Long-term ASP consumption caused interfering with testicular and ovarian hormonal activity, while vitamins C and E on the other hand, overcome longstanding consumption ASP's effects.