ATP Supplementation Research Articles

Enhancing L-Asparagine Bioproduction Efficiency Through L-Asparagine Synthetase and Polyphosphate Kinase-Coupled Conversion and ATP Regeneration.

L-Asparagine, a crucial amino acid widely used in both food and medicine, presents pollution-related and side reaction challenges when prepared using chemical synthesis method. Although biotransformation methods offer significant advantages such as high efficiency and mild reaction conditions, they also entail increased costs due to the need for ATP supplementation. This study aimed to address the challenges associated with biopreparation of L-asparagine. Firstly, the functionality and characteristics of recombinant L-asparagine synthetase enzymes derived from Escherichia coli and Lactobacillus salivarius were evaluated to determine their practical applicability. Subsequently, recombinant expression of polyphosphate kinase from Erysipelotrichaceae bacterium was conducted. A reaction system for L-asparagine synthesis was established using a dual enzyme-coupled conversion approach. Under the optimal reaction conditions, a maximum yield of 11.67 g/L of L-asparagine was achieved, with an 88.43% conversion rate, representing a 5.03-fold increase compared to the initial conversion conditions. Notably, the initial addition of ATP was reduced to only 5.66% of the theoretical demand, indicating the effectiveness of our ATP regeneration system. These findings highlight the potential of our approach in enhancing the efficiency of L-asparagine preparation, offering promising prospects for the food and medical industries.

Energy substrate supplementation increases ATP levels and is protective to PD neurons

Alteration of mitochondrial metabolism by various mutations or toxins leads to various neurological conditions. Age-related changes in energy metabolism could also play the role of a trigger for neurodegenerative disorders. Nonetheless, it is not clear if restoration of ATP production or supplementation of brain cells with substrates for energy production could be neuroprotective. Using primary neurons and astrocytes, and neurons with familial forms of neurodegenerative disorders we studied whether various substrates of energy metabolism could improve mitochondrial metabolism and stimulate ATP production, and whether increased ATP levels could protect cells against glutamate excitotoxicity and neurodegeneration. We found that supplementation of neurons with several substrates, or combination thereof, for the TCA cycle and cellular respiration, and oxidative phosphorylation resulted in an increase in mitochondrial NADH level and in mitochondrial membrane potential and led to an increased level of ATP in neurons and astrocytes. Subsequently, these cells were protected against energy deprivation during ischemia or glutamate excitotoxicity. Provision of substrates for energy metabolism to cells with familial forms of Parkinson's disease also prevented triggering of cell death. Thus, restoration of energy metabolism and increase of ATP production can play neuroprotective role in neurodegeneration. A combination of a succinate salt of choline and nicotinamide provided the best results.

Protective effects of l-cysteine and N-acetyl-l-cysteine on boar sperm quality during hypothermic liquid storage with bovine serum albumin as a protectant

Hypothermic liquid storage at 4–5 °C has emerged as a novel approach for preserving boar semen, offering innovative possibilities for semen preservation. However, this method also presents challenges, including cold shock and excessive reactive oxygen species (ROS) production. Therefore, reducing oxidative damage induced by low temperatures becomes essential while supplementing appropriate protectants. In this study, we investigated the efficacy of Bovine Serum Albumin (BSA) compared to Polyvinylpyrrolidone (PVP) and Skim Milk Powder (SMP) in maintaining boar sperm motility and progressive motility using computer-assisted sperm analysis (CASA). Among the tested concentrations, 4 g/L of BSA exhibited the best protective effect. Subsequently, we supplemented different concentrations of l-cysteine (LC) and N-acetyl-l-cysteine (NAC) as additives in the presence of BSA as a protectant. Our results demonstrated that 1 mmol/L of LC and 0.5 mmol/L of NAC exhibited superior protection of sperm quality compared to other concentrations. Furthermore, the 1 mmol/L LC and 0.5 mmol/L NAC groups showed significantly improved plasma membrane integrity and acrosome integrity compared to the control group. These groups also exhibited enhanced antioxidant capacity, evidenced by increased mitochondrial membrane potential (MMP), ATP production, total superoxide dismutase (T-SOD) activity, total antioxidant capacity (T-AOC), glutathione (GSH), glutathione peroxidase (GSH-PX), and GPX-4 levels. Additionally, they demonstrated decreased reactive oxygen species (ROS) and malondialdehyde (MDA) levels, as well as reduced oxidized glutathione (GSSG) and glutathione reductase (GR) levels. Furthermore, LC and NAC treatment enhanced AMP-activated protein kinase (AMPK) phosphorylation. However, inhibiting AMPK using compound C did not inhibit the protective effects of LC and NAC on low-temperature preserved boar sperm. These findings suggest that 4 g/L BSA can serve as an effective protectant for hypothermic liquid storage of boar semen. Additionally, LC and NAC supplementation reduces oxidative damage by enhancing antioxidant capacity rather than through AMPK-mediated ATP supplementation. These results contribute to advancing the application of LC and NAC in hypothermic liquid storage of boar semen.

Effects Of Two Weeks Atp Supplementation On Performance During A Three-minute All-out Test

Effects Of Two Weeks Atp Supplementation On Performance During A Three-minute All-out Test

ATP breakdown in plasma of children limits the antimicrobial effectiveness of their neutrophils.

Neutrophils (PMNs) require extracellular ATP and adenosine (ADO) to fight bacterial infections, which often have life-threatening consequences in pediatric patients. We wondered whether the ATP and ADO levels in the plasma of children change with age and if these changes influence the antimicrobial efficacy of the PMNs of these children. We measured plasma concentrations of ATP and ADO and the activities of the enzymes responsible for the breakdown of these mediators in plasma samples from healthy children and adolescents (n = 45) ranging in age from 0.2 to 15 years. In addition, using blood samples of these individuals, we compared how effective their PMNs were in the phagocytosis of bacteria. In an experimental sepsis model with young (10 days) and adolescent mice (10 weeks), we studied how age influenced the resilience of these animals to bacterial infections and whether addition of ATP could improve the antimicrobial capacity of their PMNs. We found that plasma ATP levels correlated with age and were significantly lower in infants (< 1 year) than in adolescents (12-15 years). In addition, we observed significantly higher plasma ATPase and adenosine deaminase activities in children (< 12 years) when compared to the adolescent population. The activities of these ATP and ADO breakdown processes correlated inversely with age and with the ability of PMNs to phagocytize bacteria. Similar to their human counterparts, young mice also had significantly lower plasma ATP levels when compared to adolescent animals. In addition, we found that mortality of young mice after bacterial infection was significantly higher than that of adolescent mice. Moreover, bacterial phagocytosis by PMNs of young mice was weaker when compared to that of older mice. Finally, we found that ATP supplementation could recover bacterial phagocytosis of young mice to levels similar to those of adolescent mice. Our findings suggest that rapid ATP hydrolysis in the plasma of young children lowers the antimicrobial functions of their PMNs and that this may contribute to the vulnerability of pediatric patients to bacterial infections.

Acute ATP loss during irreversible electroporation mediates caspase independent cell death

Irreversible electroporation (IRE) has been reported to variably cause apoptosis, necrosis, oncosis or pyroptosis. Intracellular ATP is a key substrate for apoptosis which is rapidly depleted during IRE, we sought to understand whether intracellular ATP levels is a determinant of the mode of cell death following IRE. A mouse bladder cancer cell line (MB49) was treated with electric fields while increasing the number of pulses at a fixed electric field strength, and pulse width. Cell proliferation and viability and ATP levels were measured at different timepoints post-treatment. Cell death was quantified with Annexin-V/Propidium Iodide staining. Caspase activity was measure with a fluorometric kit and western blotting. A pan-caspase (Z-VAD-FMK) inhibitor was used to assess the impact of signal inhibition. We found cell death following IRE was insensitive to caspase inhibition and was correlated with ATP loss. These findings were confirmed by cell death assays and measurement of changes in caspase expression on immunoblotting. This effect could not be rescued by ATP supplementation. Rapid and acute ATP loss during IRE interferes with caspase signaling, promoting necrosis. Cell necrosis from IRE is expected to be immunostimulatory and may be effective in cancer cells that carry mutated or defective apoptosis genes.

Tri-ortho-cresyl phosphate induces axonal degeneration in chicken DRG neurons by the NAD+ pathway

Wallerian degeneration (WD) is a well-known process by which degenerating axons and myelin are cleared after nerve injury. Although organophosphate-induced delayed neuropathy (OPIDN) is characterized by Wallerian-like degeneration of long axons in human and sensitive animals, the precise pathological mechanism remains unclear. In this study, we cultured embryonic chicken dorsal root ganglia (DRG) neurons, the model of OPIDN in vitro, to investigate the underlying mechanism of axon degeneration induced by tri-ortho-cresyl phosphate (TOCP), an OPIDN inducer. The results showed that TOCP exposure time- and concentration-dependently induced a serious degeneration and fragmentation of the axons from the DRG neurons. A collapse of mitochondrial membrane potential and a dramatic depletion of ATP levels were found in the DRG neurons after TOCP treatment. In addition, nicotinamide nucleotide adenylyl transferase 2 (NMNAT2) expression and nicotinamide adenine dinucleotide (NAD+) level was also found to be decreased in the DRG neurons exposed to TOCP. However, the TOCP-induced Wallerian degeneration in the DRG neurons could be inhibited by ATP supplementation. And exogenous NAD+ or NAD+ processor nicotinamide riboside can rescue TOCP-induced ATP deficiency and prevent TOCP-induced axon degeneration of the DRG neurons. These findings may shed light on the pathophysiological mechanism of TOCP-induced axonal damages, and implicate the potential application of NAD+ to treat OPIDN.

ATPase Inhibitory Factor 1 Is Critical for Regulating Sevoflurane-Induced Microglial Inflammatory Responses and Caspase-3 Activation.

Postoperative delirium (POD) is one of the most important complications after surgery with general anesthesia, for which the neurotoxicity of general anesthetics is a high-risk factor. However, the mechanism remains largely unknown, which also hinders the effective treatment of POD. Here, we confirmed that a clinical concentration of the general anesthetic sevoflurane increased the expression of inflammatory factors and activated the caspase-3 by upregulating ATPase inhibitory factor 1 (ATPIF1) expression in microglia. Upregulation of ATPIF1 decreased the synthesis of ATP which is an important signaling molecule secreted by microglia. Extracellular supplementation with ATP attenuated the microglial inflammatory response and caspase-3 activation caused by sevoflurane or overexpression of ATPIF1. Additionally, the microglial inflammatory response further upregulated ATPIF1 expression, resulting in a positive feedback loop. Animal experiments further indicated that intraperitoneal injection of ATP significantly alleviated sevoflurane anesthesia-induced POD-related anxiety behavior and memory damage in mice. This study reveals that ATPIF1, an important protein regulating ATP synthesis, mediates sevoflurane-induced neurotoxicity in microglia. ATP supplementation may be a potential clinical treatment to alleviate sevoflurane-induced POD.

Dose Response of Acute ATP Supplementation on Strength Training Performance.

Background: Chronic oral ATP supplementation benefits cardiovascular health, muscular performance, body composition, and recovery while attenuating muscle breakdown and fatigue. A single 400 mg dose of oral ATP supplementation improved lower body resistance training performance and energy expenditure in recreational resistance trained males, however, the minimal effective dose is currently unknown.Materials and Methods: Twenty recreationally trained men (age 28.6 ± 1.0 years, body mass 81.2 ± 2.0 kg, height 175.2 ± 1.4 cm, 1RM 141.5 ± 5.0 kg) consumed a single dose of either 400 mg, 200 mg, or 100 mg ATP (PEAK ATP®, TSI USA LLC, Missoula, MT, USA) or a placebo in a randomized, placebo-controlled crossover design, separated by a one week wash out between treatments. After warm-up, participants performed 4 sets of half-squats using free-weights until movement failure separated by 2 mins of rest between sets.Results: In comparison to placebo, 400 mg ATP significantly increased the number of set 1 repetitions (+13%, p = 0.04), and numerically increased total repetitions (+7%, p = 0.19) and total weight lifted (+6%, p = 0.22). 200 mg ATP numerically increased set 1 repetitions (+4% p = 0.47), while 100 mg ATP showed no improvements over placebo. 100 mg ATP (−4%, p < 0.05) and 400 mg ATP (−4%, p = 0.11) decreased the perceived rate of exertion compared to placebo.Conclusions: In this study, the effective minimal dose of acute oral ATP supplementation during resistance exercise to increase performance was determined to be 400 mg, while as little as 100 mg showed improvements in perceived exertion.

APOE4 genotype exacerbates the depression-like behavior of mice during aging through ATP decline

Population-based studies reveal that apolipoprotein E (APOE) ε4 gene allele is closely associated with late-life depression (LLD). However, its exact role and underlying mechanism remain obscure. The current study found that aged apoE4-targeted replacement (TR) mice displayed obvious depression-like behavior when compared with age-matched apoE3-TR mice. Furthermore, apoE4 increased stress-induced depression-like behaviors, accompanied by declines in the hippocampal 5-HT (1A) radioligand [18F] MPPF uptake evidenced by positron emission tomography (PET). In [18F]-fluorodeoxyglucose PET ([18F]-FDG PET) analyses, the FDG uptake in the prefrontal cortex, temporal cortex and hippocampus of apoE4-TR mice significantly declined when compared with that of apoE3-TR mice after acute stress. Further biochemical analysis revealed that ATP levels in the prefrontal cortex of apoE4-TR mice decreased during aging or stress process and ATP supplementation effectively rescued the depression-like behaviors of elderly apoE4-TR mice. In primary cultured astrocytes from the cortex of apoE-TR mice, apoE4, when compared with apoE3, obviously decreased the mitochondrial membrane potential, mitochondrial respiration, and glycolysis in a culture time-dependent manner. Our findings highlight that apoE4 is a potential risk factor of depression in elderly population by impairing the glucose metabolism, reducing ATP level, and damaging mitochondrial functions in astrocytes, which indicates that in clinical settings ATP supplementation may be effective for elderly depression patients with apoE4 carrier.

Apigenin causes necroptosis by inducing ROS accumulation, mitochondrial dysfunction, and ATP depletion in malignant mesothelioma cells.

Apigenin, a naturally occurring flavonoid, is known to exhibit significant anticancer activity. This study was designed to determine the effects of apigenin on two malignant mesothelioma cell lines, MSTO-211H and H2452, and to explore the underlying mechanism(s). Apigenin significantly inhibited cell viability with a concomitant increase in intracellular reactive oxygen species (ROS) and caused the loss of mitochondrial membrane potential (ΔΨm), and ATP depletion, resulting in apoptosis and necroptosis in monolayer cell culture. Apigenin upregulated DNA damage response proteins, including the DNA double strand break marker phospho (p)-histone H2A.X. and caused a transition delay at the G2/M phase of cell cycle. Western blot analysis showed that apigenin treatment upregulated protein levels of cleaved caspase-3, cleaved PARP, p-MLKL, and p-RIP3 along with an increased Bax/Bcl-2 ratio. ATP supplementation restored cell viability and levels of DNA damage-, apoptosis- and necroptosis-related proteins that apigenin caused. In addition, N-acetylcysteine reduced ROS production and improved ΔΨm loss and cell death that were caused by apigenin. In a 3D spheroid culture model, ROS-dependent necroptosis was found to be a mechanism involved in the anti-cancer activity of apigenin against malignant mesothelioma cells. Taken together, our findings suggest that apigenin can induce ROS-dependent necroptotic cell death due to ATP depletion through mitochondrial dysfunction. This study provides us a possible mechanism underlying why apigenin could be used as a therapeutic candidate for treating malignant mesothelioma.

A pilot study on investigating the role of Salvia miltiorrhiza in fetal growth restriction.

To date there is no effective treatment for pregnancies complicated by fetal growth restriction (FGR). Salvia miltiorrhiza, a traditional Chinese herb has been shown to promote blood flow and improve microcirculatory disturbance. In this pilot study, we evaluated whether S. miltiorrhiza can potentially become a possible therapy for FGR. Nineteen pregnant women with FGR were treated with S. miltiorrhiza and ATP supplementation for an average of 7 days, and 17 cases received ATP supplementation as controls. The estimated fetal weights (EFWs) were measured by ultrasound after treatment, and the birthweights were recorded after birth. After treatment with S. miltiorrhiza, 7 (37%) FGR cases showed an increase in EFW to above the 10th percentile, compared with 4 (23%) FGR cases in controls (odds ratio: 1.896, 95% confidence limits (CLs): 0.44–8.144). At delivery, 10 (53%) FGR cases in the treatment group delivered babies with a birthweight above the 10th percentile, compared with 6 (35%) FGR cases in the control group (odds ratio: 2.037, 95% CL: 0.532–7.793); 80 or 64% FGR cases in the treatment group showed an increase in fetal abdominal circumference (AC) or biparietal diameter (BPD) above the 10th percentile before delivery. While 44 or 30% FGR cases in the control group showed an increase in AC or BPD. No improvement of head circumference (HC) or femur length (FL) was seen. These pilot data suggest the need for multicenter randomized clinical trials on the potential of S. miltiorrhiza to improve perinatal outcome in pregnant women complicated by FGR.

Low doses of BPA induced abnormal mitochondrial fission and hypertrophy in human embryonic stem cell-derived cardiomyocytes via the calcineurin-DRP1 signaling pathway: A comparison between XX and XY cardiomyocytes

Humans are inevitably exposed to bisphenol A (BPA) via multiple exposure ways. Thus, attention should be raised to the possible adverse effects related to low doses of BPA. Epidemiological studies have outlined BPA exposure and the increased risk of cardiovascular diseases (such as cardiac hypertrophy), which has been confirmed to be sex-specific in rodent animals and present in few in vitro studies, although the molecular mechanism is still unclear. However, whether BPA at low doses equivalent to human internal exposure level could induce cardiac hypertrophy via the calcineurin-DRP1 signaling pathway by disrupting calcium homeostasis is unknown. To address this, human embryonic stem cell (H1, XY karyotype and H9, XX karyotype)-derived cardiomyocytes (CM) were purified and applied to study the low-dose effects of BPA on cardiomyocyte hypertrophy. In our study, when H1– and H9-CM were exposed to noncytotoxic BPA (8 ng/ml), markedly elevated hypertrophic-related mRNA expression levels (such as NPPA and NPPB), enhanced cellular area and reduced ATP supplementation, demonstrated the hypertrophic cardiomyocyte phenotype in vitro. The excessive fission produced by BPA was promoted by CnAβ-mediated dephosphorylation of DRP1. At the molecular level, the increase in cytosolic Ca2+ levels by low doses of BPA could discriminate between H1– and H9-CM, which may suggest a potential sex-specific hypertrophic risk in cardiomyocytes in terms of abnormal mitochondrial fission and ATP production by impairing CnAβ-DRP1 signaling. In CnAβ-knockdown cardiomyocytes, these changes were highly presented in XX-karyotyped cells, rather than in XY-karyotyped cells.

Conversion of d-glucose to l-lactate via pyruvate by an optimized cell-free enzymatic biosystem containing minimized reactions

Cell-free synthetic enzymatic biosystem is emerging to expand the traditional biotechnological mode by utilizing a number of purified/partially purified enzymes and coenzymes in a single reaction vessel for the production of desired products from low-cost substrates. Here, a cell-free synthetic biosystem containing minimized number of reactions was designed for the conversion of d-glucose to l-lactate via pyruvate. This NADH-balanced biosystem was comprised of only 5 thermophilic enzymes without ATP supplementation. After optimization of enzyme loading amounts, buffer concentration and cofactor concentration, d-glucose was converted to l-lactate with a product yield of ∼90%. Our study has provided an emerging platform with potentials in producing pyruvate-derived chemicals, and may promote the development of cell-free synthetic enzymatic biosystems for biomanufacturing.

Folding and assembly defects of pyruvate dehydrogenase deficiency-related variants in the E1α subunit of the pyruvate dehydrogenase complex.

The pyruvate dehydrogenase complex (PDC) bridges glycolysis and the citric acid cycle. In human, PDC deficiency leads to severe neurodevelopmental delay and progressive neurodegeneration. The majority of cases are caused by variants in the gene encoding the PDC subunit E1α. The molecular effects of the variants, however, remain poorly understood. Using yeast as a eukaryotic model system, we have studied the substitutions A189V, M230V, and R322C in yeast E1α (corresponding to the pathogenic variants A169V, M210V, and R302C in human E1α) and evaluated how substitutions of single amino acid residues within different functional E1α regions affect PDC structure and activity. The E1α A189V substitution located in the heterodimer interface showed a more compact conformation with significant underrepresentation of E1 in PDC and impaired overall PDC activity. The E1α M230V substitution located in the tetramer and heterodimer interface showed a relatively more open conformation and was particularly affected by low thiamin pyrophosphate concentrations. The E1α R322C substitution located in the phosphorylation loop of E1α resulted in PDC lacking E3 subunits and abolished overall functional activity. Furthermore, we show for the E1α variant A189V that variant E1α accumulates in the Hsp60 chaperonin, but can be released upon ATP supplementation. Our studies suggest that pathogenic E1α variants may be associated with structural changes of PDC and impaired folding of E1α.

Oncogenic HSP60 regulates mitochondrial oxidative phosphorylation to support Erk1/2 activation during pancreatic cancer cell growth

HSP60 is a mitochondrial localized quality control protein responsible for maintaining mitochondrial function. Although HSP60 is considered both a tumor suppressor and promoter in different types of cancer, the role of HSP60 in human pancreatic ductal adenocarcinoma (PDAC) remains unknown. In this study, we demonstrated that HSP60 was aberrantly expressed in human pancreatic cancer tissues and cell lines. Analysis of the Cancer Genome Atlas database revealed that HSP60 expression is positively correlated with pancreatic cancer. Further, knockdown of HSP60 attenuated pancreatic ductal cancer cell proliferation and migration/invasion, whereas ectopic expression of HSP60 increased tumorigenesis. Using an in vivo tumorigenicity assay, we confirmed that HSP60 promoted the growth of pancreatic ductal cancer cells. Functional analyses demonstrated that HSP60 plays a key role in the regulation of mitochondrial function. Mechanistically, both HSP60 knockdown and oxidative phosphorylation (OXPHOS) inhibition by metformin decreased Erk1/2 phosphorylation and induced apoptosis and cell cycle arrest, whereas Erk1/2 reactivation with EGF promoted cell proliferation. Intriguingly, in vitro ATP supplementation partially restored Erk1/2 phosphorylation and promoted proliferation in PDAC cells with HSP60 knockdown and OXPHOS inhibition. These results suggest that mitochondrial ATP is an important sensor of Erk1/2 regulated apoptosis and the cell cycle in PDAC cells. Thus, our findings indicate for the first time that HSP60 may serve as a novel diagnostic target of human pancreatic cancer, and that inhibition of mitochondrial function using drugs such as metformin may be a beneficial therapeutic strategy targeting pancreatic cancer cells with aberrant function of the HSP60/OXPHOS/Erk1/2 phosphorylation axis.

Production of myo-inositol from glucose by a novel trienzymatic cascade of polyphosphate glucokinase, inositol 1-phosphate synthase and inositol monophosphatase.

Myo-inositol (inositol) is important in the cosmetics, pharmaceutical and functional food industries. Here, we report a novel pathway to produce inositol from glucose by a trienzymatic cascade system involving polyphosphate glucokinase (PPGK), inositol 1-phosphate synthase (IPS) and inositol monophosphatase (IMP). The system contained three highly active enzymes, AspPPGK from Arthrobacter sp. OY3WO11, TbIPS from Trypanosoma brucei TREU927, and EcIMP from Escherichia coli. A trienzymatic cascade reaction was implemented, and the conversion ratio from glucose to inositol reached 90%, which is promising for the enzymatic synthesis of inositol without ATP supplementation.

Different dynamics of NLRP3 inflammasome-mediated IL-1β production in GM-CSF– and M-CSF–differentiated human macrophages

IL-1β is a "master" cytokine regulating a wide variety of physiologic and immunologic processes. The most frequently studied models for NLRP3 inflammasome-mediated IL-1β production are the macrophages; however, depending on their microenvironment, they can develop into functionally different cells. Several protocols have been developed to model the diversity of these cells in vitro. Here, we report for the first time, to our knowledge, a comparative study about the dynamics and molecular mechanisms of NLRP3 inflammasome priming and activation in LPS-stimulated, human, monocyte-derived GM- or M-macrophages, differentiated in the presence of GM-CSF or M-CSF, respectively. Our results show that IL-1β production by LPS-stimulated M-macrophages is a rapid and short event that requires ATP supplementation and is attenuated, in part, by the presence of IL-10, which reduces Akt signaling. However, IL-1β production by GM-macrophages develops gradually, and these cells produce IL-1β, even in the absence of ATP supplementation, because of the constitutively active caspase-1 enzyme. We show that the membrane-bound ectonucleotidases have an important regulatory role on the IL-1β secretion in GM-macrophages. Furthermore, we provide evidence that adenosine treatment enhances LPS-primed IL-1β secretion by GM-macrophages, but not by M-macrophages. These results show that, because of the different activation status and expression levels of the NLRP3 inflammasome components, as well as the signaling activity of the pathways, the two subtypes of macrophages respond very differently to the same stimuli. For this reason, the molecular composition of the microenvironment that shapes macrophage development should be considered when research or therapeutic methods are planned to control IL-1β production.

Interaction of Beta-Hydroxy-Beta-Methylbutyrate Free Acid and Adenosine Triphosphate on Muscle Mass, Strength, and Power in Resistance-Trained Individuals

To The Editor: We have recently become aware of the article by Lowery et al. in J Strength Cond Res 30(7): 1843–1854, 2016 entitled “Interaction of Beta-Hydroxy-Beta-Methylbutyrate Free Acid and Adenosine Triphosphate on Muscle Mass, Strength, and Power in Resistance-Trained Individuals.” We have some thoughts regarding the Methods and Results sections of the article for the readership of JSCR to consider. Methodological Questions Minimal difference values were not provided for body composition variables determined by DXA. Could the authors provide ICC's, along with the SD values for lean body mass (LBM) and fat mass (FM) so that minimal difference can be determined? The authors fail to provide any citation for location of ultrasonography for assessment of skeletal muscle hypertrophy. Were records kept for total training volume completed during the intervention for each group? Was volume and load equated across groups? Results Comments We realize that one earlier study demonstrated similar findings as that of this study; however, the Kraemer et al. (1) study used less-trained subjects, as well as a multiingredient supplement containing HMB-Ca. This study also found significant elevations in postexercise testosterone levels, whereas this study did not. Could the authors expand on the potential mechanisms responsible for muscle growth (highlighting the form and dose of HMB used in this study compared with previous studies)? We are curious about the increase in LBM (8.5 kg) and significant decrease in FM observed in the resistance-trained population used. The increase in LBM is somewhat shocking, especially when compared with previous literature using HMB in athletic populations (2–4). Further explanation as to how or why these robust changes occurred would certainly benefit the reader. If no sound explanation can be made, could there have been possible errors with the DXA machine or how the data were analyzed/reported? This might help to explain why—for the most part—these authors are the only ones who have found such significant improvements in body composition after HMB and ATP supplementation (5,6). Conclusion Owing to inconsistencies in findings between this study and that of data previously published from other laboratories, we strongly encourage researchers to replicate this study in an attempt to discover comparable findings. Furthermore, the authors mention an increase in blood flow and/or an increase in training volume as possible mechanisms for muscle growth, but blood flow was not measured and training volume was not reported. We suggest future research aim to measure or track these variables to provide possible explanations for improvements in strength and body composition after HMB + ATP supplementation. In addition, we recommend measuring growth hormone and insulin-like growth factor to determine possible underlying mechanisms for the significant increases in LBM.

Haloperidol aggravates transverse aortic constriction-induced heart failure via mitochondrial dysfunction

Haloperidol is an antipsychotic drug that inhibits the dopamine D2 receptor among others. Haloperidol also binds the sigma-1 receptor (σ1R) and inhibits it irreversibly. A serious outcome of haloperidol treatment of schizophrenia patients is death due to sudden cardiac failure. Although the cause remains unclear, we hypothesized that these effects were mediated by chronic haloperidol inhibition of cardiac σ1R. To test this, we treated neonatal rat cardiomyocytes with haloperidol, exposed them to angiotensin II and assessed hypertrophy, σ1R expression, mitochondrial Ca2+ transport and ATP levels. In this context, haloperidol treatment altered mitochondrial Ca2+ transport resulting in decreased ATP content by inactivating cardiac σ1R and/or reducing its expression. We also performed transverse aortic constriction (TAC) and then treated mice with haloperidol. After two weeks, haloperidol-treated mice showed enhanced heart failure marked by deteriorated cardiac function, reduced ATP production and increasing mortality relative to TAC only mice. ATP supplementation via sodium pyruvate rescued phenotypes seen in haloperidol-treated TAC mice. We conclude that σ1R inactivation or downregulation in response to haloperidol treatment impairs mitochondrial Ca2+ mobilization, depleting ATP depletion from cardiomyocytes. These findings suggest a novel approach to mitigate haloperidol-related adverse effects in schizophrenia patients by ATP supplementation.