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1.
Surface Stability and Morphology of Calcium Phosphate Tuned by pH Values and Lactic Acid Additives: Theoretical and Experimental Study.
Chen, H, Lv, C, Guo, L, Ma, M, Li, X, Lan, Z, Huo, J, Dong, H, Zhu, X, Zhu, Q, et al
ACS applied materials & interfaces. 2022;(4):4836-4851
Abstract
The ubiquitous mineralization of calcium phosphate (CaP) facilitates biological organisms to produce hierarchically structured minerals. The coordination number and strength of Ca2+ ions with phosphate species, oxygen-containing additives, and solvent molecules played a crucial role in tuning nucleation processes and the surface stability of CaP under the simulated body fluid (SBF) or aqueous solutions upon the addition of oligomeric lactic acid (LACn, n = 1, 8) and changing pH values. As revealed by ab initio molecular dynamics (AIMD), density functional theory (DFT), and molecular dynamics (MD) simulations as well as high-throughput experimentation (HTE), the binding of LAC molecules with Ca2+ ions and phosphate species could stabilize both the pre-nucleation clusters and brushite (DCPD, CaHPO4·2H2O) surface through intermolecular electrostatic and hydrogen bonding interactions. When the concentration of Ca2+ ions ([Ca2+]) is very low, the amount of the formed precipitation decreased with the addition of LAC based on UV-vis spectroscopic analysis due to the reduced chance for the LAC capped Ca2+ ions to coordinate with phosphates and the increased solubility in the acid solution. With the increasing [Ca2+] concentration, the kinetically stable DCPD precipitation was obtained with high Ca2+ coordination number and low surface energy. Morphologies of DCPD precipitation are in plate, needle, or rod, depending on the initial pH values that were tuned by adding NH3·H2O, HCl, or CH3COOH. The prepared samples at pH ≈ 7.4 with different Ca/P ratios exhibited negative zeta potential values, which were correlated with the surface electrostatic potential distributions and potential biological applications.
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2.
Oral lactate slows gastric emptying and suppresses appetite in young males.
Pedersen, MGB, Søndergaard, E, Nielsen, CB, Johannsen, M, Gormsen, LC, Møller, N, Jessen, N, Rittig, N
Clinical nutrition (Edinburgh, Scotland). 2022;(2):517-525
Abstract
BACKGROUND Lactate serves as an alternative energy fuel but is also an important signaling metabolite. We aimed to investigate whether oral lactate administration affects appetite-regulating hormones, slows gastric emptying rate, and dampens appetite. METHODS Ten healthy male volunteers were investigated on two separate occasions: 1) following oral ingestion of D/L-Na-lactate and 2) following oral ingestion of isotonic iso-voluminous NaCl and intravenous iso-lactemic D/L-Na-lactate infusions. Appetite was evaluated by questionnaires and ad libitum meal tests were performed at the end of each study day. Gastric emptying rate was evaluated using the acetaminophen test. RESULTS Plasma concentrations of growth differential factor 15 (GDF15, primary outcome) increased following oral and iv administration of lactate (p < 0.001) with no detectable difference between interventions (p = 0.15). Oral lactate administration lowered plasma concentrations of acylated ghrelin (p = 0.02) and elevated glucagon like peptide-1 (GLP-1, p = 0.045), insulin (p < 0.001), and glucagon (p < 0.001) compared with iv administration. Oral lactate administration slowed gastric emptying (p < 0.001), increased the feeling of being "full" (p = 0.008) and lowered the "anticipated future food intake" (p = 0.007) compared with iv administration. Food intake during the ad libitum meal test did not differ between the two study days. CONCLUSION Oral lactate administration has a direct effect on the upper gastrointestinal tract, affecting gut hormone secretion, motility and appetite sensations which cannot be mediated through lactate in the systemic circulation alone. These data suggest that compounds rich in lactate may be useful in the treatment of metabolic disease. CLINICAL TRIAL REGISTRY NUMBER NCT0429981, https://clinicaltrials.gov/ct2/show/NCT04299815.
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3.
Blueberry supplementation reduces the blood lactate response to running in normobaric hypoxia but has no effect on performance in recreational runners.
Brandenburg, JP, Giles, LV
Journal of the International Society of Sports Nutrition. 2021;(1):26
Abstract
BACKGROUND Blueberries are concentrated with anthocyanins possessing antioxidant properties. As these properties counter fatigue, blueberry supplementation may improve performance and recovery, particularly in hypoxia, where oxidative stress is elevated. METHODS This study examined the effects of blueberry supplementation on running performance, physiological responses, and recovery in normobaric hypoxia. Eleven experienced runners completed a 30-minute time-trial (TT) in normobaric hypoxia (%O2 = 15.5 %) on separate days after supplementation with four days of blueberries (BLU) or four days of placebo (PLA). Heart rate (HR), oxygen saturation (SaO2) and ratings of perceived exertion (RPE) were monitored during the TT. Blood lactate and fraction of exhaled nitric oxide (FENO) were assessed pre-TT, post-TT, and during recovery. RESULTS No significant differences were observed in the distance run during the TT, HR, SaO2, and RPE. The post-TT increase in blood lactate was significantly lower in BLU than PLA (p = 0.036). Pre-TT and post-TT FENO did not differ between conditions. Blood lactate recovery following the TT was similar between conditions. CONCLUSIONS Four days of blueberry supplementation did not alter running performance or cardiovascular and perceptual responses in normobaric hypoxia. Supplementation lowered the blood lactate response to running, however, the significance of this finding is uncertain given the absence of an ergogenic effect.
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4.
Lactic acid production from co-fermentation of food waste and spent mushroom substance with Aspergillus niger cellulase.
Ma, X, Gao, M, Wang, N, Liu, S, Wang, Q, Sun, X
Bioresource technology. 2021;:125365
Abstract
The feasibility of co-fermentation of food waste and spent mushroom substance for lactic acid with Aspergillus niger cellulase replacing commercial cellulase was explored. In this study, Enterococcus mundtii was used in this study because it could utilize hexose and pentose. When the ratio of food waste and spent mushroom substance was 1:2, lactic acid concentration was 39.22 g/L, 39.28% higher than the weighted average of experimental lactic acid concentrations, indicating that the co-fermentation had positive synergistic effects. Results showed 92.62% of sugars of pretreated spent mushroom substance was released by Aspergillus niger cellulase. Moreover, when Aspergillus niger cellulase was added into the lactic acid fermentation system at 24 h, lactic acid concentration reached 48.72 g/L, which was 22.97% higher than that of the control group with commercial cellulase, because of the disappearance of Veillonella and Saccharomycetales with the Aspergillus niger cellulase addition, thus making more substrates converted into lactic acid.
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5.
Effect of sodium-chloride ion difference on pH regulation.
Nozawa, H, Tsuboi, N, Nariai, R, Nishimura, N, Nakagawa, S
Clinical biochemistry. 2021;:75-77
Abstract
BACKGROUND In the Stewart approach, the difference between the cation and anion concentrations, especially between sodium, accounting for the majority of cations, and chloride, comprising the majority of anions, is an important factor in pH regulation. This study investigated the effect of sodium-chloride ion difference (SCD) on pH regulation comparing with those of PaCO2 and lactate. METHODS Arterial blood gas samples measured at our pediatric intensive care unit of a tertiary children's hospital between January and June 2020 were included. Samples that met the following criteria were excluded: samples collected from patients taking potassium bromide and samples with lactate concentration of >25 mmol/L. From the eligible data, pH was chosen as the dependent variable and SCD, lactate, and PaCO2 as independent variables, and then, a multiple regression analysis was performed. RESULTS In total, 5360 samples were included. Of these, five samples were excluded according to the exclusion criteria. Finally, 5355 samples were analyzed. As the variance inflation factors were <2.0 for all three variables, there was no multicollinearity. The following model was derived: pH = 7.384 + [0.97 × SCD (mEq/L) - 0.66 × PaCO2 (mmHg) - 1.33 × Lac (mmol/L)] × 10-2 (adjusted R-squared = 0.73; P value < 0.001). Based on the standardized partial regression coefficients (β), pH was affected in the order of PaCO2 (βPaCO2 = -0.95), SCD (βSCD = 0.72), and lactate (βlactate = -0.33). CONCLUSIONS The prevention of SCD reduction, together with respiratory and metabolic management, is important for pH regulation.
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6.
Lactate modulation of immune responses in inflammatory versus tumour microenvironments.
Certo, M, Tsai, CH, Pucino, V, Ho, PC, Mauro, C
Nature reviews. Immunology. 2021;(3):151-161
Abstract
The microenvironment in cancerous tissues is immunosuppressive and pro-tumorigenic, whereas the microenvironment of tissues affected by chronic inflammatory disease is pro-inflammatory and anti-resolution. Despite these opposing immunological states, the metabolic states in the tissue microenvironments of cancer and inflammatory diseases are similar: both are hypoxic, show elevated levels of lactate and other metabolic by-products and have low levels of nutrients. In this Review, we describe how the bioavailability of lactate differs in the microenvironments of tumours and inflammatory diseases compared with normal tissues, thus contributing to the establishment of specific immunological states in disease. A clear understanding of the metabolic signature of tumours and inflammatory diseases will enable therapeutic intervention aimed at resetting the bioavailability of metabolites and correcting the dysregulated immunological state, triggering beneficial cytotoxic, inflammatory responses in tumours and immunosuppressive responses in chronic inflammation.
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7.
Optimization of Initial Cation Concentrations for L-Lactic Acid Production from Fructose by Lactobacillus pentosus Cells.
Wang, J, Jiang, S, Huang, J, Guo, H, Bi, X, Hou, M, Chen, X, Hou, S, Lin, H, Lu, Y, et al
Applied biochemistry and biotechnology. 2021;(5):1496-1512
Abstract
In this study, Box-Behnken design was applied to optimize the initial concentrations of 4 cations for L-lactic acid production from fructose by homologous batch fermentation of Lactobacillus pentosus cells. The optimum initial cation concentrations were obtained as 6.542 mM Mg2+, 3.765 mM Mn2+, 2.397 mM Cu2+, and 3.912 mM Fe2+, respectively. The highest L-lactic acid yield and productivity were obtained as 0.935 ± 0.005 g/g fructose and 1.363 ± 0.021 g/(L × h), respectively, with a maximum biomass concentration of 7.97 ± 0.17 g/L. The effectiveness of the optimization by Box-Behnken design was confirmed based on the small errors between predicted results and experimental results shown as 0.3%, - 0.2%, and - 1.2%, respectively. The quadratic models with high accuracy and reliability can be applied to mathematically forecasted the fermentation performance. After the optimization, the lactic acid yield and productivity were significantly improved by 3.7% and 21.0%, respectively.
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8.
Combination of Model for End-Stage Liver Disease and Lactate Predicts Death in Patients Treated With Salvage Transjugular Intrahepatic Portosystemic Shunt for Refractory Variceal Bleeding.
Walter, A, Rudler, M, Olivas, P, Moga, L, Trépo, E, Robic, MA, Ollivier-Hourmand, I, Baiges, A, Sutter, O, Bouzbib, C, et al
Hepatology (Baltimore, Md.). 2021;(4):2085-2101
Abstract
BACKGROUND AND AIMS Data about the prognosis of salvage transjugular intrahepatic portosystemic shunt (TIPS) using covered stents for refractory variceal bleeding caused by portal hypertension are scarce. We aimed to assess survival and to identify predictors of mortality in these patients. APPROACH AND RESULTS One hundred sixty-four patients with cirrhosis from five centers treated with salvage TIPS between 2007 and 2017 were retrospectively divided into a derivation cohort (83 patients) and a validation cohort (81 patients). Comparisons were performed using the Mann-Whitney and Fischer's exact test. Six-week overall survival (OS) was correlated with variables on the day of the TIPS using Kaplan-Meier curves with log-rank test and univariate/multivariate analyses using the Cox model. Eighty-three patients were included in the derivation cohort (male, 78%; age, 55 years, alcohol-associated cirrhosis, 88%; Model for End-Stage Liver Disease [MELD], 19 [15-27]; arterial lactate, 3.7 mmol/L [2.0-8.3]). Six-week OS rate was 58%. At multivariate analysis, the MELD score (OR, 1.064; 95% CI, 1.005-1.126; P = 0.028) and arterial lactate (OR, 1.063; 95% CI, 1.013-1.114; P = 0.032) were associated with 6-week OS. Six-week OS rates were 100% in patients with arterial lactate ≤2.5 mmol/L and MELD score ≤ 15 and 5% in patients with lactate ≥12 mmol/L and/or MELD score ≥ 30. The 81 patients of the validation cohort had similar MELD and arterial lactate level but lower creatinine level (94 vs 106 µmol/L, P = 0.008); 6-week OS was 67%. Six-week OS rates were 86% in patients with arterial lactate ≤2.5 mmol/L and MELD score ≤ 15 and 10% for patients with lactate ≥12 mmol/L and/or MELD score ≥ 30. In the overall cohort, rebleeding rate was 15.8% at 6 weeks, and the acute-on-chronic liver failure grade (OR, 1.699; 95% CI, 1.056-1.663; P = 0.040) was independently associated with rebleeding. CONCLUSIONS After salvage TIPS, 6-week mortality remains high and can be predicted by MELD score and lactate. Survival rate at 6 weeks was >85% in patients with arterial lactate ≤2.5 mmol/L and MELD score ≤ 15, while mortality was >90% for lactate ≥12 mmol/L and/or MELD score ≥ 30.
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9.
Aquaporins with lactate/lactic acid permeability at physiological pH conditions.
Schmidt, JDR, Walloch, P, Höger, B, Beitz, E
Biochimie. 2021;:7-11
Abstract
The spectrum of putative and experimentally shown permeants of cellular water and solute channels of the ubiquitous aquaporin family is still increasing. Virtually all AQP substrates, e.g. water, glycerol, urea, hydrogen peroxide, or carbon dioxide, are permanently neutral small molecule compounds. Several reports, however, describe aquaporins that exhibit lactate permeability. Lactate in aqueous solution undergoes a pH-dependent protonation equilibrium with neutral lactic acid, which likely represents the actual substrate form passing the aquaporin channel. Certain aquaporins, however, appear to be better geared for lactate/lactic acid permeability even at low proton availability. Here, we discuss the structural properties of such aquaporins and compare them to the microbial protein family of the formate-nitrite (lactate) transporters that assume the aquaporin fold despite unrelated protein sequences.
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10.
Lactate Threshold Training Program on Patients with Multiple Sclerosis: A Multidisciplinary Approach.
Amato, A, Ragonese, P, Ingoglia, S, Schiera, G, Schirò, G, Di Liegro, CM, Salemi, G, Di Liegro, I, Proia, P
Nutrients. 2021;(12)
Abstract
Physical activity could play a key role in improving the quality of life, particularly in patients with nervous system diseases such as multiple sclerosis (MS). Through lactacid anaerobic training, this study aims to investigate the effects at a bio-psycho-physical level to counteract the chronic fatigue associated with the pathology, and to improve mental health at a psychological and neurotrophic level. Eight subjects (age: 34.88 ± 4.45 years) affected by multiple sclerosis were involved. A lactate threshold training program was administered biweekly for 12 weeks at the beginning of the study (T0), at the end of the study (T1) and at 9 months after the end of the study (T2), with physical, psychological and hematochemicals parameters, and dietary habits being tested. The results obtained confirmed that lactacid exercise can influence brain-derived neurotrophic factor (BDNF) levels as well as dehydroepiandrosterone sulfate (DHEAS) levels. In addition, levels of baseline lactate, which could be best used as an energy substrate, showed a decrease after the protocol training. Self-efficacy regarding worries and concerns management significantly increased from T0 to T1. The eating attitudes test (EAT-26) did not highlight any eating disease in the patients with a normal diet enrolled in our study. Physical exercise also greatly influenced the patients psychologically and emotionally, increasing their self-esteem. Lactate threshold training, together with dietary habits, appears to exert synergic positive effects on inflammation, neural plasticity and neuroprotection, producing preventive effects on MS symptoms and progression.