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Elevated dimethylarginine, ATP, cytokines, metabolic remodeling involving tryptophan metabolism and potential microglial inflammation characterize primary open angle glaucoma.
Pulukool, SK, Bhagavatham, SKS, Kannan, V, Sukumar, P, Dandamudi, RB, Ghaisas, S, Kunchala, H, Saieesh, D, Naik, AA, Pargaonkar, A, et al
Scientific reports. 2021;(1):9766
Abstract
Glaucoma of which primary open angle glaucoma (POAG) constitutes 75%, is the second leading cause of blindness. Elevated intra ocular pressure and Nitric oxide synthase (NOS) dysfunction are hallmarks of POAG. We analyzed clinical data, cytokine profile, ATP level, metabolomics and GEO datasets to identify features unique to POAG. N9 microglial cells are used to gain mechanistic insights. Our POAG cohort showed elevated ATP in aqueous humor and cytokines in plasma. Metabolomic analysis showed changes in 21 metabolites including Dimethylarginine (DMAG) and activation of tryptophan metabolism in POAG. Analysis of GEO data sets and previously published proteomic data sets bins genes into signaling and metabolic pathways. Pathways from reanalyzed metabolomic data from literature significantly overlapped with those from our POAG data. DMAG modulated purinergic signaling, ATP secretion and cytokine expression were inhibited by N-Ethylmaleimide, NO donors, BAPTA and purinergic receptor inhibitors. ATP induced elevated intracellular calcium level and cytokines expression were inhibited by BAPTA. Metabolomics of cell culture supernatant from ATP treated sets showed metabolic deregulation and activation of tryptophan metabolism. DMAG and ATP induced IDO1/2 and TDO2 were inhibited by N-Ethylmaleimide, sodium nitroprusside and BAPTA. Our data obtained from clinical samples and cell culture studies reveal a strong association of elevated DMAG, ATP, cytokines and activation of tryptophan metabolism with POAG. DMAG mediated ATP signaling, inflammation and metabolic remodeling in microglia might have implications in management of POAG.
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The influence of D-ribose ingestion and fitness level on performance and recovery.
Seifert, JG, Brumet, A, St Cyr, JA
Journal of the International Society of Sports Nutrition. 2017;:47
Abstract
BACKGROUND Skeletal muscle adenosine triphosphate (ATP) levels are severely depleted during and following prolonged high intensity exercise. Recovery from these lower ATP levels can take days, which can affect performance on subsequent days of exercise. Untrained individuals often suffer the stress and consequences of acute, repeated bouts of exercise by not having the ability to perform or recovery sufficiently to exercise on subsequent days. Conversely, trained individuals may be able to recover more quickly due to their enhanced metabolic systems. D-Ribose (DR) has been shown to enhance the recovery in ATP; however, it is not known if recovery and performance can be benefitted with DR ingestion. Therefore, this study was designed to determine what influence DR might have on muscular performance, recovery, and metabolism during and following a multi-day exercise regimen. METHODS The study was a double blind, crossover study in 26 healthy subjects compared 10 g/day of DR to 10 g/day of dextrose (DEX, control). All subjects completed 2 days of loading with either DR or DEX, followed by 3 additional days of supplementation and during these 3 days of supplementation, each subject underwent 60 min of high intensity interval exercise in separate daily sessions, which involved cycling (8 min of exercise at 60% and 2 min at 80% VO2max), followed by a 2 min power output (PO) test. Subjects were divided into two groups based on peak VO2 results, lower VO2 (LVO2) and higher peak VO2 (HVO2). RESULTS Mean and peak PO increased significantly from day 1 to day 3 for the DR trial compared to DEX in the LVO2 group. Rate of perceived exertion (RPE) and creatine kinase (CK) were significantly lower for DR than DEX in the LVO2 group. No differences in PO, RPE, heart rate, CK, blood urea nitrogen, or glucose were found between either supplement for the HVO2 group. CONCLUSION DR supplementation in the lower VO2 max group resulted in maintenance in exercise performance, as well as lower levels of RPE and CK. Unlike no observed benefits with DEX supplementation.
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Differences in Mitochondrial Coupling Reveal a Novel Signature of Mitohormesis in Muscle of Healthy Individuals.
Sparks, LM, Redman, LM, Conley, KE, Harper, ME, Hodges, A, Eroshkin, A, Costford, SR, Gabriel, ME, Yi, F, Shook, C, et al
The Journal of clinical endocrinology and metabolism. 2016;(12):4994-5003
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Abstract
CONTEXT Reduced mitochondrial coupling (ATP/O2 [P/O]) is associated with sedentariness and insulin resistance. Interpreting the physiological relevance of P/O measured in vitro is challenging. OBJECTIVE To evaluate muscle mitochondrial function and associated transcriptional profiles in nonobese healthy individuals distinguished by their in vivo P/O. DESIGN Individuals from an ancillary study of Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy phase 2 were assessed at baseline. SETTING The study was performed at Pennington Biomedical Research Center. PARTICIPANTS Forty-seven (18 males, 26-50 y of age) sedentary, healthy nonobese individuals were divided into 2 groups based on their in vivo P/O. INTERVENTION None. Main Outcome(s): Body composition by dual-energy x-ray absorptiometry, in vivo mitochondrial function (P/O and maximal ATP synthetic capacity) by 31P-magnetic resonance spectroscopy and optical spectroscopy were measured. A muscle biopsy was performed to measure fiber type, transcriptional profiling (microarray), and protein expressions. RESULTS No differences in body composition, peak aerobic capacity, type I fiber content, or mitochondrial DNA copy number were observed between the 2 groups. Compared with the uncoupled group (lower P/O), the coupled group (higher P/O) had higher rates of maximal ATP synthetic capacity (maximal ATP synthetic capacity, P < .01). Transcriptomics analyses revealed higher expressions of genes involved in mitochondrial remodeling and the oxidative stress response in the coupled group. A trend for higher mitonuclear protein imbalance (P = .06) and an elevated mitochondrial unfolded protein response (heat shock protein 60 protein; P = .004) were also identified in the coupled group. CONCLUSIONS Higher muscle mitochondrial coupling is accompanied by an overall elevation in mitochondrial function, a novel transcriptional signature of oxidative stress and mitochondrial remodeling and indications of an mitochondrial unfolded protein response.
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Skeletal muscle ATP synthesis and cellular H(+) handling measured by localized (31)P-MRS during exercise and recovery.
Fiedler, GB, Schmid, AI, Goluch, S, Schewzow, K, Laistler, E, Niess, F, Unger, E, Wolzt, M, Mirzahosseini, A, Kemp, GJ, et al
Scientific reports. 2016;:32037
Abstract
(31)P magnetic resonance spectroscopy (MRS) is widely used for non-invasive investigation of muscle metabolism dynamics. This study aims to extend knowledge on parameters derived from these measurements in detail and comprehensiveness: proton (H(+)) efflux, buffer capacity and the contributions of glycolytic (L) and oxidative (Q) rates to ATP synthesis were calculated from the evolutions of phosphocreatine (PCr) and pH. Data are reported for two muscles in the human calf, for each subject and over a wide range of exercise intensities. 22 subjects performed plantar flexions in a 7T MR-scanner, leading to PCr changes ranging from barely noticeable to almost complete depletion, depending on exercise protocol and muscle studied by localized MRS. Cytosolic buffer capacity was quantified for the first time non-invasively and individually, as was proton efflux evolution in early recovery. Acidification started once PCr depletion reached 60-75%. Initial and end-exercise L correlated with end-exercise levels of PCr and approximately linear with pH. Q calculated directly from PCr and pH derivatives was plausible, requiring fewer assumptions than the commonly used ADP-model. In conclusion, the evolution of parameters describing cellular energy metabolism was measured over a wide range of exercise intensities, revealing a relatively complete picture of muscle metabolism.
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Heat induces adenosine triphosphate release from mast cells in vitro: a putative mechanism for moxibustion.
Hu, L, Wang, L, Wei, J, Ryszard, G, Shen, X, Wolfgang, S
Journal of traditional Chinese medicine = Chung i tsa chih ying wen pan. 2015;(3):323-8
Abstract
OBJECTIVE To investigate the role of adenosine tri-phosphate (ATP) purinergic signaling in mast cells (MCs) modulated by heat to further understand the molecular mechanisms of moxibustion. METHODS Skin temperatures induced by monkshood cake moxibustion were evaluated by measuring the Neiguan acupoint (PC 6) from 31 participants with a digital thermocouple thermometer. Temperatures of 43 °C and 52 °C were applied to cultured human leukemia mast cell line HMC-1 in vitro. Calcium fluorescence was applied to detect intracellular Ca2+ ([Ca2+]). Extracellular ATP contents were measured by luciferin-luciferase assay. RESULTS Maximum skin temperatures mostly ranged from 40-45 °C , but some reached up to 50 °C. Both 43 °C and 52 °C induced MC degranulation, which was accompanied by an increase in [Ca2+] and ATP release. Complexing extracellular Ca2+ with 5 mM ethylene glycol-bis (β-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) inhibited the noxious, heat-induced elevation of [Ca2+]i and prevented the enhanced ATP secretion by those. cells at 52 °C, but not 43 °C. CONCLUSION Monkshood cake moxibustion can generate heat sufficient to trigger cellular events of MCs, including degranulation, [Ca2+]i elevation, and ATP release, suggesting that purinergic signals originating from MCs are possibly the initiating response of acupoints to moxibustion.
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Low adenosine triphosphate activity in CD4+ cells predicts infection in patients with lupus nephritis.
Liu, J, Pan, Y, Tang, LJ, Bao, JF, Hao, J, Yu, Q, Yuan, WJ, Jin, HM
Clinical and experimental rheumatology. 2014;(3):383-9
Abstract
OBJECTIVES The ImmuKnow (Cylex) assay has been reported to predict the risk of infection in some diseases; however, it is uncertain whether ImmuKnow can predict the risk of infection in lupus nephritis (LN) patients receiving immunosuppressive therapy. METHODS The ImmuKnow Immune Cell Function Assay (Cylex, Inc., Columbia, MD, USA) was applied to measure the activity of CD4+ T cells, as a marker of global immune-competence. The correlation between changes in T cell activation and the relative risk of over-immunosuppression as well as infection was studied. The amount of adenosine triphosphate (ATP) produced by CD4+ T cells in response to phytohemagglutinin (PHA) was measured for 74 LN patients without infection, 22 LN patients with severe infection (i.e. required hospitalisation), and 28 healthy controls. RESULTS No correlation was found between the ATP level and systemic lupus erythematosus (SLE) activity. The mean ATP level was significantly lower in LN patients with infection than that in healthy controls (p<0.01) and non-infected LN patients (p<0.01). The mean ATP level in non-infected LN patients was not significantly different compared to healthy controls. A cut-off ATP value of 300 ng/mL predicted infection in LN patients with a specificity of 77% and a sensitivity of 77%. Multi-variable partial correlation coefficient between the ATP assay and severe infection was r =-0.040, p<0.001; CRP was r=0.962, p<0.001. CONCLUSIONS The ImmuKnow assay may be effective in identifying an increased risk of infection in LN patients but is not correlated with SLE activity. Combined CRP value will increase the diagnostic rate of severe infection in SLE. Larger studies are required to establish clinical advantages of this assay in SLE treatment.
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Histamine induces ATP release from human subcutaneous fibroblasts, via pannexin-1 hemichannels, leading to Ca2+ mobilization and cell proliferation.
Pinheiro, AR, Paramos-de-Carvalho, D, Certal, M, Costa, MA, Costa, C, Magalhães-Cardoso, MT, Ferreirinha, F, Sévigny, J, Correia-de-Sá, P
The Journal of biological chemistry. 2013;(38):27571-27583
Abstract
Changes in the regulation of connective tissue ATP-mediated mechano-transduction and remodeling may be an important link to the pathogenesis of chronic pain. It has been demonstrated that mast cell-derived histamine plays an important role in painful fibrotic diseases. Here we analyzed the involvement of ATP in the response of human subcutaneous fibroblasts to histamine. Acute histamine application caused a rise in intracellular Ca(2+) ([Ca(2+)]i) and ATP release from human subcutaneous fibroblasts via H1 receptor activation. Histamine-induced [Ca(2+)]i rise was partially attenuated by apyrase, an enzyme that inactivates extracellular ATP, and by blocking P2 purinoceptors with pyridoxal phosphate-6-azo(benzene-2,4-disulfonic acid) tetrasodium salt and reactive blue 2. [Ca(2+)]i accumulation caused by histamine was also reduced upon blocking pannexin-1 hemichannels with (10)Panx, probenecid, or carbenoxolone but not when connexin hemichannels were inhibited with mefloquine or 2-octanol. Brefeldin A, an inhibitor of vesicular exocytosis, also did not block histamine-induced [Ca(2+)]i mobilization. Prolonged exposure of human subcutaneous fibroblast cultures to histamine favored cell growth and type I collagen synthesis via the activation of H1 receptor. This effect was mimicked by ATP and its metabolite, ADP, whereas the selective P2Y1 receptor antagonist, MRS2179, partially attenuated histamine-induced cell growth and type I collagen production. Expression of pannexin-1 and ADP-sensitive P2Y1 receptor on human subcutaneous fibroblasts was confirmed by immunofluorescence confocal microscopy and Western blot analysis. In conclusion, histamine induces ATP release from human subcutaneous fibroblasts, via pannexin-1 hemichannels, leading to [Ca(2+)]i mobilization and cell growth through the cooperation of H1 and P2 (probably P2Y1) receptors.
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Significant reduction of ATP production in PHA-activated CD4+ cells in 1-day-old blood from transplant patients.
Suviolahti, E, Petrosyan, A, Mirocha, J, Ge, S, Karasyov, A, Thomas, D, Galera, O, Lim, W, Jimenez, AM, Czer, LS, et al
Transplantation. 2012;(12):1243-9
Abstract
BACKGROUND Global immunosuppression can be measured by assessing adenosine triphospate (ATP) levels in mitogen-stimulated CD4+ T cells. METHODS We investigated the effect of storage time on ATP levels in 234 blood samples from 18 healthy individuals and 152 transplant patients. The difference between day 0 (<13 hours post-blood draw) and day 1 (24-37 hours) measurements was analyzed and compared with various factors; a subset of samples was also analyzed in 6-hour intervals. RESULTS The ATP levels were significantly lower on day 1 compared with that on day 0 in healthy individuals (279±159 vs 414±159 ng/mL, P<0.001) and patients (356±209 vs 455±221 ng/mL, P<0.0001). Of the 18 healthy individuals, 17 showed ATP reduction, whereas 192 (89%) of 216 patients did so on day 1 (24.8±24.1%). In the time course analysis, ATP levels decreased with the blood storage time in healthy and patient samples, and the reduction began as early as 7 hours post-blood draw. The reduction rate was significantly higher in patient samples with low day 0 ATP levels compared with samples with moderate or high levels (44.7±31.3% vs 23.2±23.6% or 18.7±15.7%; P<0.001). The reduction rate in patients treated with alemtuzumab induction was slightly higher than that in daclizumab-treated patients (28.8±24.6% vs 21.3±21.3%, P=0.09). CD4+ cell number did not change within 24 hours post-blood draw, but CD4 expression decreased 2.0±2.8% (P<0.05). CONCLUSIONS The ATP levels are significantly lower in 1-day-old blood compared with fresh blood, suggesting that fresh blood should be used for assessing the T cell immune function to obtain the most accurate results.
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Impaired insulin stimulation of muscular ATP production in patients with type 1 diabetes.
Kacerovsky, M, Brehm, A, Chmelik, M, Schmid, AI, Szendroedi, J, Kacerovsky-Bielesz, G, Nowotny, P, Lettner, A, Wolzt, M, Jones, JG, et al
Journal of internal medicine. 2011;(2):189-99
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Abstract
OBJECTIVE in type 2 diabetic patients and their first-degree relatives, insulin resistance (IR) is associated with impairment of insulin-stimulated myocellular glucose-6-phosphate (g6p) and unidirectional flux through ATP synthase (fATP), suggesting the presence of inherited abnormal mitochondrial oxidative fitness. We hypothesized that patients with long-standing type 1 diabetes may also exhibit insulin resistance as well as lower fATP. DESIGN this single-centre trial was registered at ClinicalTrials.gov (NCT00481598). SUBJECTS we included eight nonobese type 1 diabetic patients (mean diabetes duration: 17 years) with near-target glycaemic control [haemoglobin A1c (HbA1c): 6.8 ± 0.4%] during treatment with continuous subcutaneous insulin infusion pumps and eight healthy volunteers (HbA1c: 5.4 ± 0.2%) of comparable age, body mass and level of physical activity. OUTCOME MEASURES myocellular fATP, g6p and intramyocellular lipid content (IMCL) were measured with (1) H/(31) P magnetic resonance spectroscopy during fasting and hyperinsulinaemic-euglycaemic clamp tests. RESULTS fasting fATP, g6p and IMCL did not differ between groups. During stimulation by insulin, type 1 diabetic patients exhibited approximately 50% (P < 0.001) lower whole-body glucose disposal along with approximately 42% (P = 0.003) lower intramyocellular g6p and approximately25% (P = 0.024) lower fATP. Insulin-stimulated fATP correlated positively with whole-body insulin sensitivity (R = 0.706, P = 0.002) and negatively with HbA1c (R = -0.675, P = 0.004). CONCLUSIONS despite documented near-target glycaemic control for 1 year, nonobese patients with long-standing type 1 diabetes can exhibit insulin resistance. This associates with lower insulin-stimulated flux through muscular ATP synthase which could result from glucose toxicity.
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Individualized tumor response testing for prediction of response to Paclitaxel and Cisplatin chemotherapy in patients with advanced gastric cancer.
Kim, JH, Lee, KW, Kim, YH, Lee, KH, Oh, DY, Kim, J, Yang, SH, Im, SA, Choi, SH, Bang, YJ
Journal of Korean medical science. 2010;(5):684-90
Abstract
The purpose of our study was to determine the most accurate analytic method to define in vitro chemosensitivity, using clinical response as reference standard in prospective clinical trial, and to assess accuracy of adenosine triphosphate-based chemotherapy response assay (ATP-CRA). Forty-eight patients with chemo-naïve, histologically confirmed, locally advanced or metastatic gastric cancer were enrolled for the study and were treated with combination chemotherapy of paclitaxel 175 mg/m(2) and cisplatin 75 mg/m(2) for maximum of six cycles after obtaining specimen for ATP-CRA. We performed the receiver operator characteristic curve analysis using patient responses by WHO criteria and ATP-CRA results to define the method with the highest accuracy. Median progression free survival was 4.2 months (95% confidence interval [CI]: 3.4-5.0) and median overall survival was 11.8 months (95% CI: 9.7-13.8) for all enrolled patients. Chemosensitivity index method yielded highest accuracy of 77.8% by ROC curve analysis, and the specificity, sensitivity, positive and negative predictive values were 95.7%, 46.2%, 85.7%, and 75.9%. In vitro chemosensitive group showed higher response rate (85.7% vs. 24.1%) (P=0.005) compared to chemoresistant group. ATP-CRA could predict clinical response to paclitaxel and cisplatin chemotherapy with high accuracy in advanced gastric cancer patients. Our study supports the use of ATP-CRA in further validation studies.