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Lactate in Sarcoma Microenvironment: Much More than just a Waste Product.
Taddei, ML, Pietrovito, L, Leo, A, Chiarugi, P
Cells. 2020;(2)
Abstract
Sarcomas are rare and heterogeneous malignant tumors relatively resistant to radio- and chemotherapy. Sarcoma progression is deeply dependent on environmental conditions that sustain both cancer growth and invasive abilities. Sarcoma microenvironment is composed of different stromal cell types and extracellular proteins. In this context, cancer cells may cooperate or compete with stromal cells for metabolic nutrients to sustain their survival and to adapt to environmental changes. The strict interplay between stromal and sarcoma cells deeply affects the extracellular metabolic milieu, thus altering the behavior of both cancer cells and other non-tumor cells, including immune cells. Cancer cells are typically dependent on glucose fermentation for growth and lactate is one of the most heavily increased metabolites in the tumor bulk. Currently, lactate is no longer considered a waste product of the Warburg metabolism, but novel signaling molecules able to regulate the behavior of tumor cells, tumor-stroma interactions and the immune response. In this review, we illustrate the role of lactate in the strong acidity microenvironment of sarcoma. Really, in the biological context of sarcoma, where novel targeted therapies are needed to improve patient outcomes in combination with current therapies or as an alternative treatment, lactate targeting could be a promising approach to future clinical trials.
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2.
Lactic Acid Fermentation of Cereals and Pseudocereals: Ancient Nutritional Biotechnologies with Modern Applications.
Petrova, P, Petrov, K
Nutrients. 2020;(4)
Abstract
Grains are a substantial source of macronutrients and energy for humans. Lactic acid (LA) fermentation is the oldest and most popular way to improve the functionality, nutritional value, taste, appearance and safety of cereal foods and reduce the energy required for cooking. This literature review discusses lactic acid fermentation of the most commonly used cereals and pseudocereals by examination of the microbiological and biochemical fundamentals of the process. The study provides a critical overview of the indispensable participation of lactic acid bacteria (LAB) in the production of many traditional, ethnic, ancient and modern fermented cereals and beverages, as the analysed literature covers 40 years. The results reveal that the functional aspects of LAB fermented foods are due to significant molecular changes in macronutrients during LA fermentation. Through the action of a vast microbial enzymatic pool, LAB form a broad spectrum of volatile compounds, bioactive peptides and oligosaccharides with prebiotic potential. Modern applications of this ancient bioprocess include the industrial production of probiotic sourdough, fortified pasta, cereal beverages and "boutique" pseudocereal bread. These goods are very promising in broadening the daily menu of consumers with special nutritional needs.
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Does Low-Level Laser Therapy Decrease Muscle-Damaging Mediators After Performance in Soccer Athletes Versus Sham Laser Treatment? A Critically Appraised Topic.
Bettleyon, J, Kaminski, TW
Journal of sport rehabilitation. 2020;(8):1210-1213
Abstract
Clinical Scenario: Low-level laser therapy (LLLT) is a controversial topic for its use in athletic recovery, mainly due to inconsistency in research regarding the application of LLLT. Articles on LLLT have assessed its effectiveness in untrained humans through pain scales, functional scales, and blood draws, and it has been found capable in nonathletic rehabilitative use. The controversy lies with LLLT in the recovering athlete. Not only do athletes need to perform at high levels, but each sport is unique in the metabolic demands placed on the athletes' bodies. This modality can alter chemical mediators of the inflammatory process, specifically blood lactate (BL) and creatine kinase (CK). During soccer contests, it is a common problem for athletes to have an average CK level of 800 U/L and BL of 8 mmol·L, increasing delayed-onset muscle soreness and fatigue. Micro-CK level elevation is associated with cellular membrane damage, localized hypoxia, and electrolyte imbalances, hindering the recovery process. Clinical Question: Does LLLT decrease muscle-damaging mediators effecting player fatigue and delayed-onset muscle soreness after performance in soccer athletes versus sham treatment? Summary of Key Findings: In 3 studies, preperformance, postperformance, or preperformance and postperformance LLLT was performed and evaluated BL (2 of 3) and CK (2 of 3). In each article, BL and CK showed a significant decrease (P < .05) when performed either preperformance or postperformance versus the control group. The greatest decrease in these mediators was noticed when postperformance laser therapy was performed. Clinical Bottom Line: LLLT at 10, 30, or 50 J performed at a minimum of 2 locations on the rectus femoris, vastus lateralis, and vastus medialis bilaterally for 10 seconds each is significant in decreasing blood serum levels of BL and CK when performed postexercise. Strength of Recommendations: All 3 articles obtained a Physiotherapy Evidence Database score of ≥8/10.
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Plasma Lactate as a Marker for Metabolic Health.
Broskey, NT, Zou, K, Dohm, GL, Houmard, JA
Exercise and sport sciences reviews. 2020;(3):119-124
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Abstract
Blood lactate concentrations traditionally have been used as an index of exercise intensity or clinical hyperlactatemia. However, more recent data suggest that fasting plasma lactate can also be indicative of the risk for subsequent metabolic disease. The hypothesis presented is that fasting blood lactate accumulation reflects impaired mitochondrial substrate use, which in turn influences metabolic disease risk.
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The role of lactic acid production by probiotic Lactobacillus species in vaginal health.
Tachedjian, G, Aldunate, M, Bradshaw, CS, Cone, RA
Research in microbiology. 2017;(9-10):782-792
Abstract
Vaginal eubiosis is characterised by beneficial lactobacillus-dominated microbiota. In contrast, vaginal dysbiosis (e.g. bacterial vaginosis, BV), characterised by an overgrowth of multiple anaerobes, is associated with an increased risk of adverse urogenital and reproductive health outcomes. A major distinguishing feature between the vaginal environment in states of eubiosis and dysbiosis is a high concentration of lactic acid, produced by lactobacilli, that acidifies the vagina in eubiosis versus a sharp drop in lactic acid and an increase in pH in dysbiosis. Here we review the antimicrobial, antiviral and immunomodulatory properties of lactic acid and the use of lactic acid and lactobacilli probiotics in preventing or treating BV.
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The human vaginal microbial community.
Vaneechoutte, M
Research in microbiology. 2017;(9-10):811-825
Abstract
Monopolization of the vaginal econiche by a limited number of Lactobacillus species, resulting in low pH of 3.5-4.5, has been shown to protect women against vaginal dysbiosis, sexually transmitted infections and adverse pregnancy outcomes. Still, controversy exists as to which characteristics of lactobacilli are most important with regard to colonization resistance and to providing protection. This review addresses the antimicrobial and anti-inflammatory roles of lactic acid (and low pH) and hydrogen peroxide (and oxidative stress) as means of lactobacilli to dominate the vaginal econiche.
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Na(+)/H(+) antiporter (NHE1) and lactate/H(+) symporters (MCTs) in pH homeostasis and cancer metabolism.
Counillon, L, Bouret, Y, Marchiq, I, Pouysségur, J
Biochimica et biophysica acta. 2016;(10):2465-80
Abstract
The Na(+)/H(+)-exchanger NHE1 and the monocarboxylate transporters MCT1 and MCT4 are crucial for intracellular pH regulation, particularly under active metabolism. NHE1, a reversible antiporter, uses the energy provided by the Na(+) gradient to expel H(+) ions generated in the cytosol. The reversible H(+)/lactate(-) symporters MCT1 and 4 cotransport lactate and proton, leading to the net extrusion of lactic acid in glycolytic tumors. In the first two sections of this article we review important features and remaining questions on the structure, biochemical function and cellular roles of these transporters. We then use a fully-coupled mathematical model to simulate their relative contribution to pH regulation in response to lactate production, as it occurs in highly hypoxic and glycolytic tumor cells. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Screening and characterization of novel bacteriocins from lactic acid bacteria.
Zendo, T
Bioscience, biotechnology, and biochemistry. 2013;(5):893-9
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Abstract
Bacteriocins produced by lactic acid bacteria (LAB) are expected to be safe antimicrobial agents. While the best studied LAB bacteriocin, nisin A, is widely utilized as a food preservative, various novel ones are required to control undesirable bacteria more effectively. To discover novel bacteriocins at the early step of the screening process, we developed a rapid screening system that evaluates bacteriocins produced by newly isolated LAB based on their antibacterial spectra and molecular masses. By means of this system, various novel bacteriocins were identified, including a nisin variant, nisin Q, a two-peptide bacteriocin, lactococcin Q, a leaderless bacteriocin, lacticin Q, and a circular bacteriocin, lactocyclicin Q. Moreover, some LAB isolates were found to produce multiple bacteriocins. They were characterized as to their structures, mechanisms of action, and biosynthetic mechanisms. Novel LAB bacteriocins and their biosynthetic mechanisms are expected for applications such as food preservation and peptide engineering.
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Intraguild predation provides a selection mechanism for bacterial antagonistic compounds.
Leisner, JJ, Haaber, J
Proceedings. Biological sciences. 2012;(1747):4513-21
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Abstract
Bacteriocins are bacterial proteinaceous toxins with bacteriostatic or bacteriocidal activity towards other bacteria. The current theory on their biological role concerns especially colicins, with underlying social interactions described as an example of spite. This leads to a rock-paper-scissors game between colicin producers and sensitive and resistant variants. The generality of this type of selection mechanism has previously been challenged with lactic acid bacterial (LAB) bacteriocins as an example. In the natural environment of LAB, batch cultures are the norm opposed to the natural habitats of Escherichia coli where continuous cultures are prevailing. This implies that fitness for LAB, to a large degree, is related to survival rates (bottleneck situations) rather than to growth rates. We suggest that the biological role of LAB bacteriocins is to enhance survival in the stationary growth phase by securing a supply of nutrients from lysed target cells. Thus, this social interaction is an example of selfishness rather than of spite. Specifically, it fits into an ecological model known as intraguild predation (IGP), which is a combination of competition and predation where the predator (LAB bacteriocin producer) and prey (bacteriocin susceptible bacteria) share similar and often limited resources. We hypothesize that IGP may be a common phenomenon promoting microbial production of antagonistic compounds.
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Current status and emerging role of glutathione in food grade lactic acid bacteria.
Pophaly, SD, Singh, R, Pophaly, SD, Kaushik, JK, Tomar, SK
Microbial cell factories. 2012;:114
Abstract
Lactic acid bacteria (LAB) have taken centre stage in perspectives of modern fermented food industry and probiotic based therapeutics. These bacteria encounter various stress conditions during industrial processing or in the gastrointestinal environment. Such conditions are overcome by complex molecular assemblies capable of synthesizing and/or metabolizing molecules that play a specific role in stress adaptation. Thiols are important class of molecules which contribute towards stress management in cell. Glutathione, a low molecular weight thiol antioxidant distributed widely in eukaryotes and Gram negative organisms, is present sporadically in Gram positive bacteria. However, new insights on its occurrence and role in the latter group are coming to light. Some LAB and closely related Gram positive organisms are proposed to possess glutathione synthesis and/or utilization machinery. Also, supplementation of glutathione in food grade LAB is gaining attention for its role in stress protection and as a nutrient and sulfur source. Owing to the immense benefits of glutathione, its release by probiotic bacteria could also find important applications in health improvement. This review presents our current understanding about the status of glutathione and its role as an exogenously added molecule in food grade LAB and closely related organisms.