Fibroblast Growth Factor 21 as a Potential Biomarker for Improved Locomotion and Olfaction Detection Ability after Weight Reduction in Obese Mice

Mitigation of gestational diabetes-induced endothelial dysfunction through FGF21-NRF2 pathway activation involving L-Cystine

Gestational diabetes mellitus (GDM) disrupts glucolipid metabolism, endangering maternal and fetal health. Despite limited research on its pathogenesis and treatments, we conducted a study using serum samples from GDM-diagnosed pregnant women. We performed metabolic sequencing to identify key small molecule metabolites and explored their molecular interactions with FGF21. We also investigated FGF21's impact on GDM using blood samples from affected women. Our analysis revealed a novel finding: elevated levels of L-Cystine in GDM patients. Furthermore, we observed a positive correlation between L-Cystine and FGF21 levels, and found that L-Cystine induces NRF2 expression via FGF21 for a period of 96 h. Under high glucose (HG) conditions, FGF21 upregulates NRF2 and downstream genes NQO1 and EPHX1 via AKT phosphorylation induced by activation of IRS1, enhancing endothelial function. Additionally, we confirmed that levels of FGF21, L-Cystine, and endothelial function at the third trimester were effectively enhanced through appropriate exercise and diet during pregnancy in GDM patients (GDM + ED). These findings suggest FGF21 as a potential therapeutic agent for GDM, particularly in protecting endothelial cells. Moreover, elevated L-Cystine via appropriate exercise and diet might be a potential strategy to enhance FGF21's efficacy.

Leptin deficiency-caused behavioral change - A comparative analysis using EthoVision and DeepLabCut

Introduction

Obese rodents e.g., the leptin-deficient (ob/ob) mouse exhibit remarkable behavioral changes and are therefore ideal models for evaluating mental disorders resulting from obesity. In doing so, female as well as male ob/ob mice at 8, 24, and 40 weeks of age underwent two common behavioral tests, namely the Open Field test and Elevated Plus Maze, to investigate behavioral alteration in a sex- and age dependent manner. The accuracy of these tests is often dependent on the observer that can subjectively influence the data.

Methods

To avoid this bias, mice were tracked with a video system. Video files were further analyzed by the compared use of two software, namely EthoVision (EV) and DeepLabCut (DLC). In DLC a Deep Learning application forms the basis for using artificial intelligence in behavioral research in the future, also with regard to the reduction of animal numbers.

Results

After no sex and partly also no age-related differences were found, comparison revealed that both software lead to almost identical results and are therefore similar in their basic outcomes, especially in the determination of velocity and total distance movement. Moreover, we observed additional benefits of DLC compared to EV as it enabled the interpretation of more complex behavior, such as rearing and leaning, in an automated manner.

Discussion

Based on the comparable results from both software, our study can serve as a starting point for investigating behavioral alterations in preclinical studies of obesity by using DLC to optimize and probably to predict behavioral observations in the future.

The effect of different weight loss strategies to treat non-alcoholic fatty liver disease focusing on fibroblast growth factor 21

Objective

Obesity, often associated with non-alcoholic fatty liver disease (NAFLD), is characterized by an imbalance between energy expenditure and food intake, which is also reflected by desensitization of fibroblast growth factor 21 (FGF21). FGF21 is strongly influenced, among others, by TNFα, which is known to be upregulated in obesity-induced inflammation. Successful long-term treatments of NAFLD might be dietary modification, exercise, or fasting.

Materials and methods

Whether succeeded NAFLD recovery is linked with improved FGF21 sensitivity and finally reverted FGF21 resistance was the focus of the present study. For this purpose, mice received a high-fat diet (HFD) for 6 months to establish obesity. Afterward, the mice were subjected to three different weight loss interventions, namely, dietary change to low-fat diet (LFD), treadmill training, and/or time-restricted feeding for additional 6 months, whereas one group remained on HFD.

Results

In addition to the expected decrease in NAFLD activity with dietary change, this was also observed in the HFD group with additional time-restricted feeding. There was also an associated decrease in hepatic TNFα and FGF21 expression and an increase in ß-klotho expression, demonstrated mainly by using principal component analysis. Pearson correlation analysis shows that independent of any intervention, TNFα expression decreased with improved NAFLD recovery. This was accompanied with higher FGF21 sensitivity, as expressed by an increase in β-klotho and FGFR1c expression and concomitantly decreased FGF21 levels.

Conclusion

In summary, we conclude that successful NAFLD therapy is associated with a reversion of the TNFα-triggered FGF21-resistant state or desensitization.

Effects of aerobic exercise on fibroblast growth factor 21 in overweight and obesity. A systematic review

Fibroblast growth factor 21 (FGF21) has been suggested to improve metabolism during aerobic exercise in obesity. However, the variability of exercise interventions gives rise to discrepancies in the field. Therefore, we aimed to systematically review the available literature regarding the effects of aerobic exercise on FGF21 in the context of overweight and obesity. Our search included original articles published between 2009 and November 2021 found in PubMed, Science Direct, and Medline. Clinical and preclinical studies were included. Studies, where subjects or animals presented with other conditions (e.g., cancer, stroke), were excluded. From an initial 43 studies, 19 (clinical studies = 9; preclinical studies = 10) were eligible for inclusion in this review. The main findings were that acute exercise tended to increase circulatory levels of FGF21. In contrast, chronic exercise programs (≥4 weeks) had the opposite effect along with inducing mRNA and protein increases of FGF receptors and β-klotho in adipose tissue, liver, and skeletal muscle. In conclusion, both clinical and preclinical studies showed that aerobic exercise exerts changes in circulatory and tissue FGF21, along with its receptors and co-receptor. Future research is needed to elucidate the mechanisms, along with the physiological and clinical implications of these changes.