Bidirectional modulation of TCA cycle metabolites and anaplerosis by metformin and its combination with SGLT2i.

BACKGROUND: Metformin and sodium-glucose-cotransporter-2 inhibitors (SGLT2i) are cornerstone therapies for managing hyperglycemia in diabetes. However, their detailed impacts on metabolic processes, particularly within the citric acid (TCA) cycle and its anaplerotic pathways, remain unclear. This study investigates the tissue-specific metabolic effects of metformin, both as a monotherapy and in combination with SGLT2i, on the TCA cycle and associated anaplerotic reactions in both mice and humans. METHODS: Metformin-specific metabolic changes were initially identified by comparing metformin-treated diabetic mice (MET) with vehicle-treated db/db mice (VG). These findings were then assessed in two human cohorts (KORA and QBB) and a longitudinal KORA study of metformin-naïve patients with Type 2 Diabetes (T2D). We also compared MET with db/db mice on combination therapy (SGLT2i + MET). Metabolic profiling analyzed 716 metabolites from plasma, liver, and kidney tissues post-treatment, using linear regression and Bonferroni correction for statistical analysis, complemented by pathway analyses to explore the pathophysiological implications. RESULTS: Metformin monotherapy significantly upregulated TCA cycle intermediates such as malate, fumarate, and α-ketoglutarate (α-KG) in plasma, and anaplerotic substrates including hepatic glutamate and renal 2-hydroxyglutarate (2-HG) in diabetic mice. Downregulated hepatic taurine was also observed. The addition of SGLT2i, however, reversed these effects, such as downregulating circulating malate and α-KG, and hepatic glutamate and renal 2-HG, but upregulated hepatic taurine. In human T2D patients on metformin therapy, significant systemic alterations in metabolites were observed, including increased malate but decreased citrulline. The bidirectional modulation of TCA cycle intermediates in mice influenced key anaplerotic pathways linked to glutaminolysis, tumorigenesis, immune regulation, and antioxidative responses. CONCLUSION: This study elucidates the specific metabolic consequences of metformin and SGLT2i on the TCA cycle, reflecting potential impacts on the immune system. Metformin shows promise for its anti-inflammatory properties, while the addition of SGLT2i may provide liver protection in conditions like metabolic dysfunction-associated steatotic liver disease (MASLD). These observations underscore the importance of personalized treatment strategies.

Prediction of Myocardial Infarction Using a Combined Generative Adversarial Network Model and Feature-Enhanced Loss Function.

Accurate risk prediction for myocardial infarction (MI) is crucial for preventive strategies, given its significant impact on global mortality and morbidity. Here, we propose a novel deep-learning approach to enhance the prediction of incident MI cases by incorporating metabolomics alongside clinical risk factors. We utilized data from the KORA cohort, including the baseline S4 and follow-up F4 studies, consisting of 1454 participants without prior history of MI. The dataset comprised 19 clinical variables and 363 metabolites. Due to the imbalanced nature of the dataset (78 observed MI cases and 1376 non-MI individuals), we employed a generative adversarial network (GAN) model to generate new incident cases, augmenting the dataset and improving feature representation. To predict MI, we further utilized multi-layer perceptron (MLP) models in conjunction with the synthetic minority oversampling technique (SMOTE) and edited nearest neighbor (ENN) methods to address overfitting and underfitting issues, particularly when dealing with imbalanced datasets. To enhance prediction accuracy, we propose a novel GAN for feature-enhanced (GFE) loss function. The GFE loss function resulted in an approximate 2% improvement in prediction accuracy, yielding a final accuracy of 70%. Furthermore, we evaluated the contribution of each clinical variable and metabolite to the predictive model and identified the 10 most significant variables, including glucose tolerance, sex, and physical activity. This is the first study to construct a deep-learning approach for producing 7-year MI predictions using the newly proposed loss function. Our findings demonstrate the promising potential of our technique in identifying novel biomarkers for MI prediction.

Metabolic effects of SGLT2i and metformin on 3-hydroxybutyric acid and lactate in db/db mice.

Combining a Sodium-Glucose-Cotransporter-2-inhibitor (SGLT2i) with metformin is recommended for managing hyperglycemia in patients with type 2 diabetes (T2D) who have cardio-renal complications. Our study aimed to investigate the metabolic effects of SGLT2i and metformin, both individually and synergistically. We treated leptin receptor-deficient (db/db) mice with these drugs for two weeks and conducted metabolite profiling, identifying 861 metabolites across kidney, liver, muscle, fat, and plasma. Using linear regression and mixed-effects models, we identified two SGLT2i-specific metabolites, X-12465 and 3-hydroxybutyric acid (3HBA), a ketone body, across all examined tissues. The levels of 3HBA were significantly higher under SGLT2i monotherapy compared to controls and were attenuated when combined with metformin. We observed similar modulatory effects on metabolites involved in protein catabolism (e.g., branched-chain amino acids) and gluconeogenesis. Moreover, combination therapy significantly raised pipecolate levels, which may enhance mTOR1 activity, while modulating GSK3, a common target of SGLT2i and 3HBA inhibition. The combination therapy also led to significant reductions in body weight and lactate levels, contrasted with monotherapies. Our findings advocate for the combined approach to better manage muscle loss, and the risks of DKA and lactic acidosis, presenting a more effective strategy for T2D treatment.

The effects and mechanisms of the new brominated flame retardant BTBPE on thyroid toxicity.

As an alternative to octabromodiphenyl ether (octa-BDE), 1, 2-bis (2,4, 6-tribromophenoxy) ethane (BTBPE) has been widely used in a variety of combustible materials, such as plastics, textiles and furniture. Previous studies have demonstrated the thyroid toxicity of traditional brominated flame retardants for example octa-BDE clearly. Nevertheless, little is known about the thyroid toxicity of alternative novel brominated flame retardants BTBPE. In this study, it was demonstrated that BTBPE in vivo exposure induced FT4 reduction in 2.5, 25 and 250 mg/kg bw treated group and TT4 reduction in 25 mg/kg bw treated group. TG, TPO and NIS are key proteins of thyroid hormone synthesis. The results of Western blot and RT-PCR from thyroid tissue showed decreased protein levels and gene expression levels of TG, TPO and NIS as well as regulatory proteins PAX8 and TTF2. To investigate whether the effect also occurred in humans, anthropogenic Nthy-ori 3-1 cells were selected. Similar results were seen in vitro condition. 2.5 mg/L BTBPE reduced the protein levels of PAX8, TTF1 and TTF2, which in turn inhibited the protein levels of TG and NIS. The results in vitro experiment were consistent with that in vivo, suggesting possible thyrotoxic effects of BTBPE on humans. It was indicated that BTBPE had the potential interference of T4 generation and the study provided more evidence of the effects on endocrine disorders.

Developmental immunotoxicity of maternal exposure to yttrium nitrate on BALB/c offspring mice.

Yttrium is a typical heavy rare earth element with widespread use in numerous sectors. Only one previous study has indicated that yttrium has the potential to cause developmental immunotoxicity (DIT). Therefore, there remains a paucity of evidence on the DIT of yttrium. This study aimed to explore the DIT of yttrium nitrate (YN) and the self-recovery of YN-induced DIT. Dams were treated with 0, 0.2, 2, and 20 mg/kg bw/day YN by gavage during gestation and lactation. No significant changes were found in innate immunity between the control and YN-treated groups in offspring. In female offspring at postnatal day 21 (PND21), YN markedly inhibited humoral and cellular immune responses, the proliferative capacity of splenic T lymphocytes, and the expression of costimulatory molecules in splenic lymphocytes. Moreover, the inhibitory effect on cellular immunity in female offspring persisted to PND42. Unlike females, YN exposure did not change the adaptive immune responses in male offspring. Overall, maternal exposure to YN showed a strong DIT to offspring, with the lowest effective dose of 0.2 mg/kg in the current study. The toxicity of cellular immunity could persist throughout development into adulthood. There were sex-specific differences in YN-induced DIT, with females being more vulnerable.

1,4-Naphthoquinone-coated black carbon nanoparticles up-regulation POR/FTL/IL-33 axis in THP1 cells.

Black carbon (BC) is an important component of atmospheric PM 2.5 and the second largest contributor to global warming. 1,4-naphthoquinone-coated BC (1,4 NQ-BC) is a secondary particle with great research value, so we chose 1,4 NQ-BC as the research object. In our study, mitochondria and lysosomes were selected as targets to confirm whether they were impaired by 1,4 NQ-BC, label free proteomics technology, fluorescent probes, qRT-PCR and western blots were used to investigate the mechanism of 1,4 NQ-BC toxicity. We found 494 differentially expressed proteins (DEPs) in mitochondria and 86 DEPs in lysosomes using a proteomics analysis of THP1 cells after 1,4 NQ-BC exposure for 24 h. Through proteomics analysis and related experiments, we found that 1,4 NQ-BC can damage THP-1-M cells by obstructing autophagy, increasing lysosomal membrane permeability, disturbing the balance of ROS, and reducing the mitochondrial membrane potential. It is worth noting that 1,4 NQ-BC prevented the removal of FTL by inhibiting autophagy, and increased IL-33 level by POR/FTL/IL-33 axis. We first applied proteomics to study the damage mechanism of 1,4 NQ-BC on THP1 cells. Our research will enrich knowledge of the mechanism by which 1,4 NQ-BC damages human macrophages and identify important therapeutic targets and adverse outcome pathways for 1,4 NQ-BC-induced damage.

Maternal cerium nitrate exposure induces developmental immunotoxicity in BALB/c mouse offspring.

With the increasing application of cerium and rare-earth elements (REEs), cerium exposure is becoming more widespread. However, there remains a paucity of evidence on developmental immunotoxicity of cerium. This study was designed to examine the developmental immunotoxicity of gestational and postnatal exposure to cerium nitrate (CN) in BALB/C mouse offspring. Dams were given CN by oral gavage at 0, 0.002, 0.02 and 0.2 mg/kg from gestation day 5 (GD5) to postnatal day 21 (PND 21). On PND 21, the highest dose of CN significantly suppressed the NK cell cytotoxicity, and reduced the proportions of NK cells in peripheral blood and spleen of both female and male pups, however, the proportions of monocytes in peripheral blood and macrophages in spleen only increased in female pups. For adaptive immunity, on PND 21, the suppression of T/B lymphocyte proliferation, humoral and cellular immune responses (number of splenic plaque-forming cells, PFC, and delayed-type hypersensitivity, DTH) were observed in both female and male pup mice exposed to 0.2 mg/kg CN. However, the fall of proportions of T/B lymphocytes in peripheral blood (PB), spleen and mesenteric lymph node (MLN) only found in female pups at 0.2 mg/kg on PND 21. Most indications recovered to normal after 3-week cessation of CN exposure, except the reduction of DTH and PFC. From the findings in this study, the lowest-observed-adverse-effect level (LOAEL) of CN for developmental immunotoxicity was estimated to be 0.2 mg/kg bw per day.

Integrated proteomic analysis to explore the molecular regulation mechanism of IL-33 mRNA increased by black carbon in the human endothelial cell line EA.hy926.

Black carbon (BC) correlates with the occurrence and progression of atherosclerosis and other cardiovascular diseases. Increasing evidence has demonstrated that BC could impair vascular endothelial cells, but the underlying mechanisms remain obscure. It is known that IL-33 exerts a significant biological role in cardiovascular disease, but little is known about the molecular regulation of IL-33 expression at present. We first found that BC significantly increased IL-33 mRNA in EA.hy926 cells in a concentration and time-dependent manner, and we conducted this study to explore its underlying mechanism. We identified that BC induced mitochondrial damage and suppressed autophagy function in EA.hy926 cells, as evidenced by elevation of the aspartate aminotransferase (GOT2), reactive oxygen species (ROS) and p62, and the reduction of mitochondrial membrane potential (ΔΨm). However, ROS cannot induce IL-33 mRNA-production in BC-exposed EA.hy926 cells. Further, experiments revealed that BC could promote IL-33 mRNA production through the PI3K/Akt/AP-1 and p38/AP-1 signaling pathways. It is concluded that BC could induce oxidative stress and suppress autophagy function in endothelial cells. This study also provided evidence that the pro-cardiovascular-diseases properties of BC may be due to its ability to stimulate the PI3K/AKT/AP-1 and p38/AP-1 pathway, further activate IL-33 and ultimately result in a local vascular inflammation.

Exploration of potential mechanism of interleukin-33 up-regulation caused by 1,4-naphthoquinone black carbon in RAW264.7 cells.

BACKGROUND: As air pollution has been paid more attention to by public in recent years, effects and mechanism in particulate matter-triggered health problems become a focus of research. Lysosomes and mitochondria play an important role in regulation of inflammation. Interleukin-33 (IL-33) has been proved to promote inflammation in our previous studies. In this research, macrophage cell line RAW264.7 was used to explore the potential mechanism of upregulation of IL-33 induced by 1,4-naphthoquinone black carbon (1,4-NQ-BC), and to explore changes of lysosomes and mitochondria during the process. RESULTS: 50 µg/mL 1,4-NQ-BC exposure for 24 h dramatically increased expression of IL-33 in RAW264.7 cells. Lysosomal membrane permeability was damaged by 1,4-NQ-BC treatment, and higher mitochondrial membrane potential and ROS level were induced by 1,4-NQ-BC. The results of proteomics suggested that expression of ferritin light chain was increased after cells were challenged with 1,4-NQ-BC, and it was verified by Western blot. Meanwhile, expressions of p62 and LC3B-II were increased by 50 µg/mL 1,4-NQ-BC in RAW264.7 cells. Ultimately, expression of IL-33 could return to same level as control in cells treated with 50 µg/mL 1,4-NQ-BC and 50 µM deferoxamine combined. CONCLUSIONS: 1,4-NQ-BC induces IL-33 upregulation in RAW264.7 cells, and it is responsible for higher lysosomal membrane permeability and ROS level, lower mitochondrial membrane potential, and inhibition of autophagy. Ferritin light chain possibly plays an important role in the upregulation of IL-33 evoked by 1,4-NQ-BC.

Associations of maternal exposure to fine particulate matter with preterm and early-term birth in high-risk pregnant women.

BACKGROUND: Environmental pollution is a risk factor for adverse birth outcomes, especially preterm birth (PTB) and early-term birth (ETB). It has been revealed that exposure to fine particulate matter (PM2.5) during pregnancy increase the prevalence of PTB. However, the relationship between PM2.5 exposure and ETB has not been elucidated. In high-risk pregnancies, whether PM2.5 exposure will bring higher risk of PTB and ETB than in normal pregnancies is still unclear, and the susceptible exposure window is obscure. Therefore, it is worthy of assessing the risk on PTB and ETB and identifying the susceptible exposure windows of PM2.5 exposure in high-risk pregnant women. RESULTS: This paper collected the clinical data of 7974 singletons, high-risk pregnant women in Peking University First Hospital from 2014 to 2018, and analyzed them using logistic regression and stratified analysis. We observed that exposure to high-level (≥ 75 µg/m3) of PM2.5 during the third trimester of pregnancy increases the risk of PTB and ETB (PTB: odds ratio[OR] = 1.43, 95% confidence interval [CI]:1.05-1.93. ETB: OR = 1.29, 95%CI: 1.09-1.54). Furthermore, the effects of each 10ug/m3 increase in PM2.5 on PTB and ETB were significant during the third trimester (PTB: OR = 1.35, 95%CI:1.16-1.58. ETB: OR = 1.12, 95%CI:1.02-1.22) and the entire pregnancy (PTB: OR = 6.12, 95%CI:4.27-8.89. ETB: OR = 1.96, 95%CI:1.59-2.43) in the high-level exposure group. CONCLUSIONS: These results suggest that high-level PM2.5 exposure during pregnancy is associated with high risk of PTB and ETB in high-risk pregnancies. The third trimester of pregnancy is speculated to be the susceptible exposure window.

Effects of intrauterine and lactational exposure to lanthanum nitrate on BALB/c offspring mice: Developmental immunotoxicity and self-recovery.

Lanthanum, a major rare earth element, can exert detrimental effects on the adult immune system, but its developmental immunotoxicity (DIT) remains obscure. This study was designed to evaluate the DIT of lanthanum nitrate (LN) and the self-recovery of LN-induced DIT 21 days following cessation of exposure. BALB/c pregnant dams were exposed to 0, 0.1, 1, and 10 mg/kg body weight/day LN by gavage during gestation and lactation. Results showed that in male offspring, LN markedly inhibited the adaptive immunity at postanal day 21 (PND21) and the inhibitory effect on cellular immunity continued to PND42 (after three weeks of self-recovery). In female offspring, LN suppressed cellular immunity at both PND21 and PND42. Moreover, decreased relative organ weight of thymus, humoral immunity and proportion of double-positive T cells in thymus were also observed at PND42. Bcl-xl protein level decreased in thymus of female at PND42, while the level of ß-catenin increased. These changes might contribute to accelerating the degeneration and weight loss of thymus. Overall, in-utero and postanal exposure to LN could induce impairments of immunity in offspring, especially the female, and adaptive immunosuppression would persist throughout development into adulthood. The LOAEL of LN for DIT should be 1 mg/kg.

BC and 1,4NQ-BC up-regulate the cytokines and enhance IL-33 expression in LPS pretreatment of human bronchial epithelial cells☆.

Black carbon (BC) reacts with different substances to form secondary pollutants called aged black carbon, which causes inflammation and lung damage. BC and aged BC may enhance IL-33 in vivo, which may be derived from macrophages. The pro-inflammatory effect of IL-33 makes it essential to determine the source of IL-33, so it guides us to explore how to alleviate lung injury. In this study, a human bronchial epithelial cell line of 16HBE cells was selected, and aged BC (1,4-NQ coated BC and ozone oxidized BC) was used. We found that both BC and aged BC were able to up-regulate the mRNA expression of IL-1ß, IL-6, and IL-8 except IL-33. However, the Mitogen-activated protein kinases (MAPKs) and Phosphatidylinositol 3-kinase (PI3K)/Protein kinase B (AKTs) pathways remained inactive. After pretreatment with Lipopolysaccharide (LPS), IL-33 mRNA expression was significantly increased in 16HBE cells and MAPKs and PI3K/AKT were activated. These results suggested that MAPKs and PI3K/AKT pathways were involved in the elevation of IL-33. Furthermore, epithelial cells are unlikely to be the source of lung inflammation caused by elevated IL-33 in BC and aged BC.

Enhancement in the enzymatic digestibility of hybrid poplar with poor residual hemicelluloses after Na2SO3 pretreatment.

The aim of this work was to illustrate the contributions of delignification and the introduced sulfonic groups on the enzymatic digestibility of the Na2SO3-pretreated hybrid poplar with poor residual hemicelluloses (HPPRH). The higher the content of the introduced sulfonic group in the pretreated HPPRH was, the higher its enzymatic digestibility could be achieved. Delignification was favorable to increasing the content of sulfonic group in the pretreated HPPRH. The introduced sulfonic group contributed much more to the total glucose yield at low level of residual lignin. The introduced sulfonic groups could contribute 17.30% of total glucose yield (92.70%) and delignification could do 38.43% of it. Meanwhile, the delignification rate and the sulfonic group content in the pretreated HPRH were 59.88% and 283.51mmolkg(-1) lignin, respectively. Therefore, the sulfonic group introduced on the pretreated lignocellulosics could improve the enzymatic digestibility and make the sulfite process effective.

Efficient extraction and characterization of polymeric hemicelluloses from hybrid poplar.

Hemicelluloses were isolated from hybrid poplar with the single-step alkaline extraction. Neutralization and subsequent ethanol precipitation were used to recover them. Their structures were investigated using sugar analysis, Fourier transform infrared and (13)C nuclear magnetic resonance spectroscopy. The hemicelluloses were characterized by particle size analyzer, gel permeation chromatography and thermogravimetric analyzer. 36.4% and 50.4% of the original hemicelluloses were isolated in the form of polymer by neutralization and precipitation, respectively. The hemicellulosic fraction (HA) by neutralization was more homogeneous in sugar components than the one (HB) by precipitation. However, hemicellulose isolated by both of the process has chemical structure, as were (4-O-methylglucurono)-d-xylans. The weight average molecular mass of HA was 17,480 g mol(-1), higher than one of HB (14,670 g mol(-1)) and they were both with a low polydispersity. HA had lower zeta potential and higher thermal stability than HB. Therefore, the procedures in this study were efficient for the isolation and the recovery of polymeric hemicelluloses with different properties.

Practicability and safety of laser-assisted reduction surgery.

We have presented an innovative laser-assisted reduction surgery (LARS) based on plasma-induced ablation and photodisruption effects. In addition, we developed a laser operation system. Fetuses of mice from the Institute for Cancer Research that were immersed in physiological saline were irradiated by convergent-pulsed laser with a wavelength of 1064 nm, pulse width of 6 ns, and pulse energy of 50 mJ. The hearts of the postirradiated fetuses were significantly damaged, which resulted in rapid fetal death. We also substantiated the safety of LARS by analyzing the heat distribution of the induced laser pulse with thermal distribution equations. The results demonstrate that this innovative method for pregnancy reduction is feasible.

Axial nano-displacement measurement with high resolution and wide range based on asymmetrical illumination.

We propose a novel axial nano-displacement measuring approach. Based on asymmetrical illumination, the axial drifts of the sample plane can be measured by detecting the position of the centroid of the focal spot. Both CCD and QD are used as the detector in the system and two data processing models are designed. With a relatively simple and applicable configuration, the proposed system can realize a wide measuring range of >4λand a high axial resolution of 2nm. Moreover, the presented approach is immune to the influence caused by the energy fluctuation of the laser source. Possessing these advantages, this measuring method has big potential to be applied in modern engineering and scientific researches.

Breaking the diffraction barrier using fluorescence emission difference microscopy.

We propose a novel physical mechanism for breaking the diffraction barrier in the far field. Termed fluorescence emission difference microscopy (FED), our approach is based on the intensity difference between two differently acquired images. When fluorescence saturation is applied, the resolving ability of FED can be further enhanced. A detailed theoretical analysis and a series of simulation tests are performed. The validity of FED in practical use is demonstrated by experiments on fluorescent nanoparticles and biological cells in which a spatial resolution of <λ/4 is achieved. Featuring the potential to realize a high imaging speed, this approach may be widely applied in nanoscale investigations.

Optical super-resolution by subtraction of time-gated images.

Applying image subtraction strategy together with time-gated detection, we can reveal finer details in a fixed cell sample using moderate light intensities. The subtractive imaging is obtained from the subtraction of a suitably weighted short lifetime intensity-image from a long lifetime one, while the weight coefficient can be selected using the analysis of an optical transfer function. Compared with other subtractive methods, ours is regarded as an optimized variation of gated stimulated emission depletion microscopy and can be implemented in a simpler manner, providing lateral super-resolution, and it is theoretically possible to further expand its application scope.

Fluorescence lifetime imaging with pulsed diode laser enabled stimulated emission.

We present here a stimulated emission based fluorescence lifetime imaging (FLIM) scheme using a pair of synchronized diode lasers operating at gain switched pulse mode. The two semiconductor lasers, with wavelengths at 635 nm and 700 nm, serve as the excitation and the stimulation light sources for the ATTO647N labeled sample, respectively. FLIM is readily achieved with their relative time delay controlled electronically. The coherent nature of the stimulated emission signal also allows FLIM at long working distance. In this way, a high performance all-semiconductor FLIM module is realized in a flexible, compact, and cost effective configuration.

Influences of spherical aberration on resonator's stable zones and fundamental mode output power scaling of solid state laser oscillators.

A parameter x is introduced to characterize the strength of thermal lens spherical aberration, whose influences on resonator's stable zones are analyzed theoretically. Some new and helpful results are obtained. For symmetrical plane-plane cavity, spherical aberration has just influence on the back edge of stable zone. For asymmetrical plane-plane cavity, spherical aberration has influence on the back edges of the two stable zones and the front edge of the second stable zone. Effects of transverse mode collapsing to TEM00 mode and stable zones separation of different order's transverse modes are pointed out, which is the foundation of TEM00 mode output power scaling for solid state laser oscillator. Influences of parameters such as resonator's long arm length, short arm length, and pump beam radius on the extent to which of stable zones separation of different order transverse modes are discussed. An experimental setup of a high power diodes dual-end pumped Nd:YVO4 TEM00 mode laser oscillator is built up and investigated experimentally. 51.2 W TEM00 mode output power in CW operation is achieved with an optical-to-optical efficiency of about 50% and beam quality factor M2 being 1.2.