High Glucose Concentrations Research Articles

An Aqueous Electrolyte Gated Artificial Synapse with Synaptic Plasticity Selectively Mediated by Biomolecules

AbstractThe emulation of functions and behaviors of biological synapses using electronic devices has inspired the development of artificial neural networks (ANNs) in biomedical interfaces. Despite the achievements, artificial synapses that can be selectively responsive to non‐electroactive biomolecules and directly operate in biological environments are still lacking. Herein, we report an artificial synapse based on organic electrochemical transistors and investigate the selective modulation of its synaptic plasticity by glucose. The enzymatic reaction between glucose and glucose oxidase results in long‐term modulation of the channel conductance, mimicking selective binding of biomolecules to their receptors and consequent long‐term modulation of the synaptic weight. Moreover, the device shows enhanced synaptic behaviors in the blood serum at a higher glucose concentration, which suggests its potential application in vivo as artificial neurons. This work provides a step towards the fabrication of ANNs with synaptic plasticity selectively mediated by biomolecules for neuro‐prosthetics and human‐machine interfaces.

An Aqueous Electrolyte Gated Artificial Synapse with Synaptic Plasticity Selectively Mediated by Biomolecules.

The emulation of functions and behaviors of biological synapses using electronic devices has inspired the development of artificial neural networks (ANNs) in biomedical interfaces. Despite the achievements, artificial synapses that can be selectively responsive to non-electroactive biomolecules and directly operate in biological environments are still lacking. Herein, we report an artificial synapse based on organic electrochemical transistors and investigate the selective modulation of its synaptic plasticity by glucose. The enzymatic reaction between glucose and glucose oxidase results in long-term modulation of the channel conductance, mimicking selective binding of biomolecules to their receptors and consequent long-term modulation of the synaptic weight. Moreover, the device shows enhanced synaptic behaviors in the blood serum at a higher glucose concentration, which suggests its potential application in vivo as artificial neurons. This work provides a step towards the fabrication of ANNs with synaptic plasticity selectively mediated by biomolecules for neuro-prosthetics and human-machine interfaces.

Biochemical response of two earthworm taxa exposed to freezing.

Several earthworm species are known to be able to withstand freezing. At the biochemical level, this ability is based on cryoprotectant accumulation as well as several other mechanisms. In this study, we used 1H NMR to investigate metabolomic changes in two freeze-tolerant earthworm taxa, Dendrobaena octaedra and one of the genetic lineages of Eisenia sp. aff. nordenskioldi f. pallida. A total of 45 metabolites were quantified. High concentrations of glucose were present in frozen tissues of both taxa. No other putative cryoprotectants were found. We detected high levels of glycolysis end products and succinate in frozen animals, indicating the activation of glycolysis. Concentrations of many other substances also significantly increased. On the whole, metabolic change in response to freezing was much more pronounced in the specimens of Eisenia sp. aff. nordenskioldi f. pallida, including signs of nucleotide degradation.

Underutilized Crocus Sativus L. Flowers: A Hidden Source of Sustainable High Value-Added Ingredients

Crocus sativus L. is used as a spice due to its organoleptic characteristics. Only flower stigmas are used for its production, as the rest of the flower is discarded as waste. This fact represents a lack of sustainability, since around 230,000 flowers are necessary to produce 1 kg of saffron. The main aim of this study was to contribute to the valorization of Crocus sativus L. spice and its floral by-products, through the study of their nutritional value and composition, in terms of hydrophilic and lipophilic compounds, as well as their functional properties. The results showed that saffron stigmas and floral bio-residues presented high contents of fiber, and the most abundant macronutrient were the carbohydrates, followed by proteins, and a low content in fats. All samples had high concentrations of glucose, fructose, lactic and malic acids, and minerals, mainly K, Ca and Mg. Furthermore, the polyunsaturated fatty acids were predominant, being linoleic acid (C18:2n6) the most abundant. Therefore, this research provides more in-depth information about the composition of saffron stigmas and floral by-products, to be considered as promising sources for the development of functional ingredients with new applications in the food industry.

Influence of lactational status of the surrogate mare during early pregnancy on inflammatory markers in subsequently born foals

Nutrition during pregnancy has a significant impact on the offspring and affects health, growth and metabolism in several species, including equines. Studies have associated orthopedic problems in foals, such as osteochondritis dissecans (OCD), with diet of the broodmare during pregnancy resulting in high glucose concentrations, causing suppression of the central regulation of growth hormone (GH) secretion and subsequent disruption of the GH/IGF-1 (insulin-like growth factor-1) axis. It is very common to use non-lactating mares as embryo recipients, however little is known about the effect of lactational status on pregnant mare metabolism and the effect on the resulting embryo, fetus and the offspring's metabolism and development. Our study aimed to compare inflammatory cytokines, osteocalcin and IGF-1 in foals born from lactating recipient mares (LM; n=7) and non-lactating recipient mares (NLM; n=5) from days 1-28 after birth. Twelve healthy Mangalarga Paulista mares aged 5 to 15 years of age were used. Twelve foals, eight males and four females, born by eutocia were evaluated. Recipient LMs were lactating from the day of ovulation, until a maximum of 170 days of pregnancy (124 to 170). Foal evaluations were performed at birth (D1) and at 7, 14, 21 and 28 days of age (D7, D14, D21 and D28). Leptin (ng/mL), adiponectin (µg/mL), resistin (ng/mL) analyses were performed using ELISA, and interleukin6 (IL6; pg/mL), interleukin 10 (IL10; pg/mL), tumor necrosis factor (TNFα; pg/mL), osteocalcin (ng/mL) and IGF-1 (ng/mL) were evaluated using immunoassay kits. We used a factorial arrangement between group (LM x NLM) and time (D1, D7, D14, D21 and D28). The results are the mean and standard error of the mean. There was no significant interaction in any of the variables. Concentrations of IGF-1, IL6, IL10 and TNFα were higher in the NLM group (IGF1: 29.48±3.82 vs 176.53±65.8, p=0.0002; IL6:9.89±0.74 vs 13.57±1.33, p=0.01; IL10: 75.37±3.89 vs 100.75±8.84, p=0.0006 and TNFα: 8.08±1.08 vs 12.89±1.75, p<0.001). Only in IL10 concentration, there was a difference over time (D1: 114.11±1.04; D7: 72.08±8.13; D14: 12±6.96; D21: 72.98±5.25 and D28:100.44±9.25; p<0.001). Osteocalcin correlated positively with leptin (p<0.05; r=0.27). In this study, the recipient mares’ lactational status during the first trimester of pregnancy influenced concentrations of inflammatory markers in the subsequently born foal up to 28 days of life, with higher concentrations of IGF-1, IL6, IL10 and TNFα than in foals born from non-lactating recipient mares. This raises an important discussion on the impact of lactational status of the recipient dam on the future of her offspring. Acknowledgements: FAPESP (2017/05425-0 and 2020/10260-3) and CAPES

Optimization of fermentation conditions as a metabolic strategy for the high-yield and high-selectivity bio-based 2,3-butanediol production

Optimization of culture conditions can be used as an alternative metabolic control strategy to genetic engineering to improve bio-based 2,3-butanediol (2,3-BDO) production, especially its yield and optical purity. In this study, a first-order model was determined to predict the 2,3-BDO yield, which reached about 90% in batch cultures at 32° C, pH = 5, and kLa ∼ 5.0 ± 2.7 h−1, using a new and safe Paenibacillus peoriae NRRL BD-62. No acetoin accumulation and an absolute levo-2,3-BDO optical purity were also verified. About 39.4 g/L of 2,3-BDO, with a yield of 0.43 g/g, and a levo-:meso-2,3-BDO ratio of 1.9:1, was obtained at the expense of acetoin, lactic acid, and ethanol in fed-batch fermentation at kLa adjusted within its optimized range (∼7.5 h−1) to overcome operational limitations using high initial glucose concentrations. The low pH contributed to the carbon flux shift toward the levo-isomer synthesis, possibly due to the preferential butanediol dehydrogenase activation, while the highly oxygen-limited environment favored the complete acetoin conversion, enhancing the 2,3-BDO yield. These results provide significant contributions to the high-yield, acetoin-free, and safe bio-based 2,3-BDO production of particular interest in large-scale fermentations.

Pyruvate enhances stallion sperm function increasing glycolysis efficiency through NAD+

Pyruvate entry into the mitochondrial matrix is a critical step for the efficient generation of reducing equivalents and ATP (Yiew and Finck, 2022). Improvements in sperm function using metabolites readily metabolizable through the tricarboxylic acid cycle (TCA), have been attributed to their ability to readily feed the electron transport chain (ETC) in the mitochondria; 8 NADH and 2 FADH2 are produced in the TCA cycle. However, noncanonical mechanisms may explain improvements in sperm functions. For example, the direct use of lactate in the TCA (Martinez-Reyes and Chandel, 2017) or a more efficient glycolysis (Hereng et al., 2011); in both mechanisms lactate dehydrogenase (LDH) plays a major role. If pyruvate improves the efficiency of glycolysis, the detrimental effects of higher glucose concentrations could be counteracted by increasing pyruvate concentration in the media. To test this hypothesis stallion spermatozoa were incubated in presence of high glucose concentration (67mM) in presence of 1- or 10-mM pyruvate. To investigate the role of LDH, we used the specific inhibitor oxamate. If our hypothesis is correct improved functionality will be observed in high pyruvate media. Flow cytometry, CASA, and metabolomics were used to disclose the potential mechanisms behind this. Stallion spermatozoa (n=4, ANOVA and Dunnett´s test) incubated for 3 h at 37°C in 67mM Tyrode´s media supplemented with 10 mM pyruvate showed increased total motility in comparison with aliquots incubated in Tyrode's 5mM glucose and Tyrode´s67mM glucose, from 57.1 ± 3.5 and 58.1 ± 1.9 to 73.0± 1.1 % (P<0.01). Spermatozoa incubated in Tyrode's with 67 mM glucose and 10mM pyruvate maintained viability along the incubation period (64.03 ± 15.4% vs 61.3 ± 10.2%), while spermatozoa incubated in 67 mM Glucose-Tyrode's showed a decrease in viability (38.01 ± 11.2, P<0.01). The presence of 40 mM oxamate (LDH inhibitor) reduced sperm viability (P<0.05, from 76± 5 % in the media containing 67 mM Glucose and 10 mM pyruvate to 68.0 ± 4.3 % in presence of oxamate, P<0.05). Apoptotic markers also increased when the LDH inhibitor oxamate was present (P<0.01). The incorporation of glucose was reduced in the presence of 10mM pyruvate, suggesting that the stallion spermatozoa have mechanisms to regulate the incorporation of this hexose. Furthermore, UHPLC/MS/MS showed that in presence of 10 mM pyruvate, the relative amounts of lactate, ATP, NAD+, and NADH increased. Our findings indicate that the mechanisms that explain the improvement of sperm function in presence of 10 mM pyruvate may involve the conversion of pyruvate to lactate producing NAD+ that improves the efficiency of glycolysis. Acknowledgements: Ministerio de Ciencia-European Fund for Regional Development (EFRD) Spain, grants PID2021-122351OB-I00 and PRE2018-083354 Junta de Extremadura-EFDR (IB 20008).

Regulation of Cat8 in energy metabolic balance and glucose tolerance in Saccharomyces cerevisiae.

Cat8 is a C6 zinc cluster transcription activator in yeast. It is generally recognized that the transcription of CAT8 is inhibited and that Cat8 is inactive in the presence of high concentrations of glucose. However, our recent study found that constitutively overexpressed Cat8 played a regulatory role in Saccharomyces cerevisiae in the presence of 20 g/L glucose. To explore the regulatory network of Cat8 at high glucose concentrations, CAT8 was both overexpressed and deleted in this study. Cell growth and glucose consumption in different media were significantly accelerated by the deletion of CAT8, while the lag period was greatly shortened. RNA-seq and genetic modification showed that the deletion of CAT8 changed the type of energy metabolism in yeast cells. Many genes related to the mitochondrial respiratory chain were downregulated, resulting in a reduction in aerobic respiration and the tricarboxylic acid cycle. Meanwhile, both the energy supply of anaerobic ethanol fermentation and the Crabtree effect of S. cerevisiae were enhanced by the deletion of CAT8. CAT8 knockout cells show a higher sugar uptake rate, a higher cell growth rate, and higher tolerance to glucose than the wild-type strain YS58. This study expands the understanding of the regulatory network of Cat8 and provides guidance for modulating yeast cell growth. KEY POINTS: • The deletion of CAT8 promoted cell growth of S. cerevisiae. • Transcriptome analysis revealed the regulation network of Cat8 under 1% glucose condition. • CAT8 deletion increases the glucose tolerance of cells by enhancing the Crabtree effect.

Growth and development of the replacement young chickens of the parent herd of the meat direction of productivity

The purpose of the research was to study the growth and development of the replacement young chickens of the parent herd of meat production and compare the eff ectiveness of the use of two complex feed additives Sorbitox and Probitox. When rearing the replacement young chickens of the cross Ross-308, the use of feed additive Sorbitox at a dose of 0,50 kg/t of feed made it possible to obtain in comparison with the control group the livability of livestock higher by 1,5 abs.%, with a similar dosage of Probitox additive by 2,1 abs.%. Analysis of the causes of culling of the replacement young chickens showed that the use of Sorbitox and Probitox additives reduced culling after two weeks of age, while in the control group it was observed throughout the entire rearing period. The average live weight of poultry of the control and experimental groups at 18 weeks of age had no signifi cant diff erences, but at the same time the uniformity of the group with Probitox additive exceeded the control by 8,7 abs.%, with Sorbitox by 5,3 abs.%. Analysis of the development of the main organs and departments of the gastrointestinal tract showed that the studied feed additives stimulated the development of the liver, heart, muscular stomach, intestines. The weight of the ovary and the length of the oviducts in the group of chickens receiving Sorbitox exceeded the control group by 20,3 and 9,7 %, with Probitox the diff erence was 27,8 and 11,4 %. Feed additives of sorption and probiotic action in the body of poultry stimulated metabolism of an anabolic nature. In the blood of the chickens receiving Sorbitox, the total protein was by 4,5 % higher than the control group, with Probitox by 5,6 %. At the same time, the level of urea decreased by 26,0 and 33,1 %. The highest glucose content was in the blood of poultry receiving Probitox additive (12,5 mmol/l), which exceeded the control group by 20,7 %, in the group with Sorbitox the diff erence was 7,3 %. The tested feed additives contributed to a greater retention of calcium in the poultry body, and also reduced expenditures of feed for rearing replacement young chickens. The use of Sorbitox additive reduced expenditures of feed by 6,9 %, and Probitox by 12,8 %.

Corrigendum to: Betaine ameliorates high glucose-induced oxidative stress in granulosa cells.

In diabetes, abnormalities of granulosa cells (GCs) and steroidogenesis are associated with hyperglycaemia-induced oxidative stress. Betaine has beneficial effect in experimental model of diabetes by reducing oxidative stress, inflammation, and apoptosis. In this study we investigate the effects of betaine to prevent oxidative stress in GCs induced by high glucose and improve steroidogenesis. Primary GCs, isolated from ovarian follicles of C57BL/6 mice were cultured in 5mM (control) and 30mM (hyperglycaemia) of glucose and in presence of 5mM of betaine for 24h. Then antioxidant enzymes, malondialdehyde, oestradiol and progesterone were measured. In addition, the expression of Nrf2 and NF-κB , antioxidant enzymes (Sod1 , Gpx and Cat ) were analysed by qRT-PCR assay. We observed significant (P NF-κB and down-regulation of Nrf2 due to high concentration of glucose. Also significant (P Cat , Sod1 and GPx ) and activity reduction of these enzymes as well as significant (P NF-κB and up-regulating the expression of Nrf2 , Cat , Sod1 and GPx . It was also shown that betaine in the presence of FSH significantly (P Conclusion: Betaine compensated the antioxidant stress in mouse GCs under hyperglycaemic condition via regulation of Nrf2/NF-κB at transcription level. As betaine is a natural product and no side effect has been reported to today, we suggest more research needs to be carried out especially on patients whom suffer from diabetes to find the probability of using betaine as a therapeutic agent.

A Copper Single‐Atom Cascade Bionanocatalyst for Treating Multidrug‐Resistant Bacterial Diabetic Ulcer

AbstractDiabetic ulcers induced by multidrug‐resistant (MDR) bacteria have severely endangered diabetic populations. These ulcers are very challenging to treat because the local high glucose concentration can both promote bacterial growth and limit the immune system's bactericidal action. Herein, a glucose oxidase‐peroxidase (GOx‐POD) dual‐enzyme mimetic (DEM) bionanocatalyst, Au@CuBCats is synthesized to simultaneously control glucose concentration and bacteria in diabetic ulcers. Specifically, the AuNPs can serve as GOx mimics and catalyze the oxidation of glucose for the formation of H2O2; the H2O2 can then be further catalytically converted into OH via the POD‐mimetic copper single atoms. Notably, the unique copper single atoms coordinated by one oxygen and two nitrogen atoms (CuN2O1) exhibit better POD catalytic performance than natural peroxidase. Further DFT calculations are conducted to study the catalytic mechanism and reveal the advantage of this CuN2O1 structure as compared to other copper single‐atom sites. Both in vitro and in vivo experiments confirm the outstanding antibacterial therapeutic efficacy of the DEM bionanocatalyst. This new bionanocatalyst will provide essential insights for the next generation of antibiotic‐free strategies for combating MDR bacterial diabetic ulcers, and also offer inspiration for designing bionanocatalytic cascading medicines.

Effect of Parquetina nigrescens (Afzel.) Leaves on Letrozole-Induced PCOS in Rats: a Molecular Insight into Its Phytoconstituents.

Polycystic ovarian syndrome (PCOS) is one of the common causes of female infertility in women of reproductive age. P. nigrescens is a plant used in the treatment of various diseases including menstrual disorders. This study investigated the effect of ethanolic extracts of P. nigrescens leaves on the estrous cycle, fasting blood glucose, and hormonal and lipid profile in letrozole-induced PCOS rats and also evaluated the molecular mechanism of the active constituents using computational methods. After the induction of PCOS with letrozole, rats were treated orally for 14days with distilled water (1mg/kg/day), clomiphene citrate (2mg/kg/day), metformin (7.14mg/kg/day), and ethanolic extract of P. nigrescens (50 and 100mg). Thereafter, selected biochemical parameters were assayed to determine the extract's effect on the estrous cycle. Molecular docking and molecular dynamics simulation (MDS) were carried out to determine the binding affinity and relative stability of the ligand-receptor complexes. Letrozole-induced PCOS rats showed irregular estrous cyclicity, elevated (p > 0.05) triglycerides, low-density lipoprotein cholesterol (LDL), total cholesterol, insulin, testosterone, and luteinizing hormone(LH) concentration, low (p > 0.05) progesterone, low follicle-stimulating hormone (FSH), high-density lipoprotein cholesterol (HDL), and high fasting blood glucose concentration compared to that of the control group. The reproductive, biochemical, and structural alterations were reversed by the administration of ethanolic extract of P. nigrescens leaves (50mg/kg) which restored the estrous cycle after 14days of treatment. However, the ethanolic extracts of P. nigrescens (100mg/kg) significantly increased (p > 0.05) FSH, HDL, and progesterone concentrations but decreased the LH, progesterone, and total cholesterol. Of all 44 compounds identified in GCMS analysis of an ethanolic extract of P. nigrescens leaves, only 2-ethylbutyl heptyl ester (CID 91705405) had a higher binding affinity for hormonal receptors and enzymes responsible for hepatic gluconeogenesis compared to standard drugs used in the study. CID 91705405 was also relatively stable over 100ns of MDS. This compound is therefore revealed to have the potential to modulate both endocrine and metabolic pathways involved in PCOS. The ethanolic extract of P. nigrescens leaves can therefore be considered in the management/treatment of the reproductive and metabolic disorders related to PCOS subject to further experimental validation.

Blood-Glucose-Depleting Hydrogel Dressing as an Activatable Photothermal/Chemodynamic Antibacterial Agent for Healing Diabetic Wounds

Poorly healing and nonhealing diabetic wounds are challenging to treat as the rapid growth of bacteria due to the high local glucose content can lead to persistent inflammation and poor angiogenesis. Herein, a smart hydrogel dressing composed of 3,3',5,5'-tetramethylbenzidine/ferrous ion/Pluronic F-127/glucose oxidase (TMB/Fe2+/PF127/GOx) is designed and demonstrated to consume blood glucose while accelerating wound healing by generating antibacterial agents in situ. The loaded GOx degrades blood glucose to provide hydrogen peroxide (H2O2) and gluconic acid to support the Fe2+-based Fenton reaction, and the generated hydroxyl radical (·OH) facilitates the oxidation of TMB. The color change from colorless to green caused by the oxidation of TMB in the blood glucose range between 1 and 10 mM can be monitored visually. Simultaneously, this process induced chemodynamic therapy (CDT) by the specific generation of hydroxyl radical (·OH) for killing bacteria. Moreover, the oxidized TMB shows strong absorption in the near infrared (NIR) region so that NIR light can be converted into heat efficiently for photothermal therapy (PTT). As a result, nearly 100% of Staphylococcus aureus and Escherichia coli are killed by synergistic PTT/CDT, and the infected skin wounds undergo complete repair along with downregulation of interleukin-6 (IL-6) and upregulation of the vascular endothelial growth factor (VEGF) and matrix metallopeptidase-2 (MMP-2). Different from traditional wound dressings that can give rise to secondary injury, the excellent thermosensitive properties arising from the sol/gel phase transition render the hydrogel dressing materials injectable, self-reparable, and removable on demand. The multifunctional hydrogel with hypoglycemic, chemodynamic, photothermal, antibacterial, and on-demand thermosensitive properties has immense potential in the treatment of diabetic wounds.

Enabling glucose adaptive self-healing hydrogel based triboelectric biosensor for tracking a human perspiration

A breakthrough in intelligent healthcare enables the collection of real-time patient data and active diagnosis via the advancement of medical technology. Monitoring glucose levels steady is essential to minimize diabetes-related issues since glucose is used by cells as an essential source of energy. Despite the range of commercially available glucose monitoring devices, the pain of repetitive blood testing and complex power demands has addressed the shortcomings of painless compact glucose biosensors. To address these drawbacks, self-healing glucose adaptive hydrogel based triboelectric biosensors (GAH-TES) are proposed as a biocompatible noninvasive technique for simultaneous glucose monitoring. With the assistance of a -cyclodextrin inclusion complex, glucose-adaptive PVA hydrogels may be utilized as an immobilization matrix for the glucose oxidase enzyme. The modulation of dynamic hydrogel networks in the presence of diversified glucose environments leads in changes in conductivity that boost electrical performance. Introducing glucose-adaptive hydrogel into a triboelectric nanogenerator (TENG) allows for efficient energy conversion from motion-based glucose stimuli in human sweat to electrical output. Higher glucose concentrations were shown to boost TENG production due to the greater conductivity and polarization effect caused by the increased ionic strength carried by the enzymatic activity. Due to its ability to detect high glucose levels autonomously, GAH-TES has broadened the scope of diabetes management by highly selective, flexible, and reliable real-time monitoring of human perspiration.

Factors associated with the risk of developing diabetes mellitus in patients with coronary artery disease

Aim to determine the factors associated with the risk of developing type 2 diabetes in patients with coronary artery disease (CAD).&#x0D; Material and methods.The retrospective data sample included 181 patients hospitalized in the cardiology department of the SamSMU clinics. The patients were divided into two groups: group 1 122 patients without type 2 diabetes (77 (63.1%) men, median age 66.0 (59.0;75.0) years) and group 2 59 patients with type 2 diabetes (29 (49.2%) men, median age 69.0 (63.0;73.5) years).&#x0D; Results.The statistically significant difference (p0.05) was registered in glomerular filtration rate (GFR); no significant differences were demonstrated in other clinical indicators, including age and gender. Expectedly, the patients with type 2 diabetes had higher glucose levels. The parameters of the lipid spectrum and creatinine did not differ between the groups.&#x0D; Conclusion.The factors associated with the risk of developing type 2 diabetes are high glucose concentration and reduced GFR. The application of the developed discriminant analysis model will allow to determine the risk group of type 2 diabetes in patients with coronary heart disease, which will ensure a timely control of the presented indicators.

Promoting β-cells function by the recapitulation of in vivo microenvironmental differentiation signals.

The study aims to transdifferentiate rat bone marrow-derived mesenchymal stem cells (BM-MSCs) more efficiently into islet-like cells and encapsulate and transplant them with vital properties like stability, proliferation, and metabolic activity enhanced for the treatment of T1DM. Trans-differentiation of BM-MCs into islet-like cells induced by high glucose concentration combined with Nicotinamide, ꞵ-Mercaptoethanol, ꞵ-Cellulin, and IGF-1. Glucose challenge assays and gene expression profiles were used to determine functionality. Microencapsulation was performed using the vibrating nozzle encapsulator droplet method with a 1% alginate concentration. Encapsulated ꞵ-cells were cultured in a fluidized-bed bioreactor with 1850 μL/min fluid flow rates and a superficial velocity of 1.15cm/min. The procedure was followed by transplanting transdifferentiated cells into the omentum of streptozotocin (STZ)-induced diabetic Wistar rats. Changes in weight, glucose, insulin, and C-peptide levels were monitored for 2months after transplantation. PDX1, INS, GCG, NKx2.2, NKx6.1, and GLUT2 expression levels revealed the specificity of generated β-cells with higher viability (about 20%) and glucose sensitivity about twofold more. The encapsulated β-cells decreased the glucose levels in STZ-induced rats significantly (P < 0.05) 1week after transplantation. Also, the weight and levels of insulin and C-peptide reached the control group. In contrast to the treated, the sham group displayed a consistent decline in weight and died when loss reached > 20% at day ~ 55. The coated cells secrete significantly higher amounts of insulin in response to glucose concentration changes. Enhanced viability and functionality of β-cells can be achieved through differentiation and culturing, a promising approach toward insulin therapy alternatives.

Matrix Metalloproteinase-7 Associated with Congestive Heart Failure in Peritoneal Dialysis Patients: A Prospective Cohort Study.

Matrix metalloproteinase-7 (MMP7) is markedly expressed in patients with chronic kidney disease; its expression in dialysate and role in patients undergoing peritoneal dialysis (PD) have not been well established. Participants undergoing PD from June 1st, 2015, to June 30th, 2020, were involved and were followed up every 3 months for the first year and every 6 months thereafter until death, PD withdrawal, or the end of the study. Data at each follow-up point were collected and analyzed for the association with congestive heart failure (CHF), PD withdrawal, and combined endpoint. A total of 283 participants were included in this study. During a median follow-up of 21 months, 20 (7%) participants died, 93 (33%) withdrew from PD, and 105 (37%) developed CHF. A significantly increased level of serum and dialysate MMP7 was observed at baseline. Dialysate MMP7 presented a good linearity with serum MMP7. Baseline serum and dialysate MMP7 levels were associated with CHF in multivariable Cox proportional hazards regression models. After categorization, participants with high baseline MMP7 levels had a higher incidence of CHF (42%), and the hazard ratios (95% confidence intervals) were 1.595 (1.023-2.488). Interestingly, participants with higher serum MMP7 levels were trended to use dialysate with higher glucose concentration. However, the ultrafiltration volumes were not significantly increased. Higher MMP7 levels were also positively associated with PD withdrawal and combined endpoint. The expression of MMP7 in serum and dialysate was markedly increased and was tightly associated with the risk of CHF in PD patients. This finding suggests that the measurement of MMP7 may inform strategies for managing CHF at an earlier stage.

Freeze-induced suppression of pyruvate kinase in liver of the wood frog (Rana sylvatica).

The wood frog (Rana sylvatica) undergoes physiological and metabolic changes to withstand subzero temperatures and whole body freezing during the winter months. Along with metabolic rate depression, high concentrations of glucose are produced as a cryoprotectant by liver and distributed to all other tissues. Pyruvate kinase (PK; EC:2.7.1.40), the final enzyme of glycolysis, plays an important role in the modulation of glucose metabolism and, therefore, overall metabolic regulation. The present study investigated the functional and kinetic properties of purified PK from liver of control (5°C acclimated) and frozen (-2.5°C for 24h) wood frogs. Liver PK was purified to homogeneity by a two-step chromatographic process, followed by analysis of enzyme properties. A significant decrease in the affinity of PK for its substrates, phosphoenolpyruvate (PEP) and adenosine diphosphate (ADP) at 22°C and 5°C was noted in liver from frozen frogs, as compared with controls. Immunoblotting also revealed freeze-responsive changes in posttranslational modifications with a significant increase in serine and threonine phosphorylation by 1.46-fold and 1.73- fold for PK from frozen frogs as compared with controls. Furthermore, a test of thermal stability showed that PK from liver of frozen wood frogs showed greater stability as compared with PK from control animals. Taken together, these results suggest that PK is negatively regulated, and glycolysis is suppressed, during freezing. This response acts as an important survival strategy for maintaining continuously elevated levels of cryoprotectant in frogs while they remain in a hypometabolic frozen state.

Intercellular contacts affect secretion and biosynthesis of pancreatic islet cells.

Cell protein biosynthesis is regulated by different factors, but implication of intercellular contacts on alpha and beta cell protein biosyntheses activity has not been yet investigated. Islet cell biosynthetic activity is essential in regulating not only the hormonal reserve within cells but also in renewing all the proteins involved in the control of secretion. Here we aimed to assess whether intercellular interactions affected similarly secretion and protein biosynthesis of rat alpha and beta cells. Insulin and glucagon secretion were analyzed by ELISA or reverse hemolytic plaque assay, and protein biosynthesis evaluated at single cell level using bioorthogonal noncanonical amino acid tagging. Regarding beta cells, we showed a positive correlation between insulin secretion and protein biosynthesis. We also observed that homologous contacts increased both activities at low or moderate glucose concentrations. By contrast, at high glucose concentration, homologous contacts increased insulin secretion and not protein biosynthesis. In addition, heterogeneous contacts between beta and alpha cells had no impact on insulin secretion and protein biosynthesis. Regarding alpha cells, we showed that when they were in contact with beta cells, they increased their glucagon secretion in response to a drop of glucose concentration, but, on the other hand, they decreased their protein biosynthesis under any glucose concentrations. Altogether, these results emphasize the role of intercellular contacts on the function of islet cells, showing that intercellular contacts increased protein biosynthesis in beta cells, except at high glucose, and decreased protein biosynthesis in alpha cells even when glucagon secretion is stimulated.

Taurine reduces apoptosis mediated by endoplasmic reticulum stress in islet β-cells induced by high-fat and -glucose diets.

Poor eating habits, especially high-fat and -glucose diets intake, can lead to endoplasmic reticulum (ER) stress in islet β-cells, insulin resistance, and islet β-cell dysfunction and cause islet β-cell apoptosis, which leads to type 2 diabetes mellitus (T2DM). Taurine is a crucial amino acid in the human body. In this study, we aimed to explore the mechanism through which taurine reduces glycolipid toxicity. INS-1 islet β-cell lines were cultured with a high concentration of fat and glucose. SD rats were fed a high-fat and -glucose diet. MTS, Transmission electron microscopy, Flow cytometry, Hematoxylin-eosin, TUNEL, Western blotting analysis and other methods were used to detect relevant indicators. The research found that taurine increases the cell activity, reduces the apoptosis rate, alleviates the structural changes of ER under high-fat and -glucose exposure models. In addition, taurine improves blood lipid content and islets pathological changes, regulates the relative protein expression in ER stress and apoptosis, increases the insulin sensitivity index (HOMA-IS), and reduces the insulin resistance index (HOMAC-IR) of SD rats fed with a high-fat and -glucose diet.