Purine Nucleotide Degradation Research Articles

Evolution of the biochemistry underpinning purine alkaloid metabolism in plants.

Purine alkaloids are naturally occurring nitrogenous methylated derivatives of purine nucleotide degradation products, having essential roles in medicine, food and various other aspects of our daily lives. They are generated through convergent evolution in different plant species. The pivotal reaction steps within the purine alkaloid metabolic pathways have been largely elucidated, and the convergent evolution of purine alkaloids has been substantiated through bioinformatic, biochemical and other research perspectives within S-adenosyl-ʟ-methionine-dependent N-methyltransferases. Currently, the biological and ecological roles of purine alkaloids, further refinement of the purine alkaloid metabolic pathways and the investigation of purine alkaloid adaptive evolutionary mechanisms continue to attract widespread research interest. The exploration of the purine alkaloid metabolic pathways also enhances our comprehension of the biochemical mechanism, providing insights into inter-species interactions and adaptive evolution and offering potential value in drug development and agricultural applications. Here, we review the progress of research in the distribution, metabolic pathway elucidation and regulation, evolutionary mechanism and ecological roles of purine alkaloids in plants. The opportunities and challenges involved in elucidating the biochemical basis and evolutionary mechanisms of the purine alkaloid metabolic pathways, as well as other research aspects, are also discussed. This article is part of the theme issue 'The evolution of plant meta-bolism'.

Chronic Pain Nursing Care for Elderly Gout Patients Using Warm Water Compress Therapy Combination Lemongrass and Ginger

Introduction: Uric acid is a normal substance found in the body and is the end result of purine metabolism, namely the result of the degradation of purine nucleotides which are important ingredients in the body as components of nucleic acids. The nursing problem that arises in elderly gout patients is chronic pain. The aim of this scientific work aims to explore nursing care for chronic pain in elderly gout patients with warm water compress therapy using lemongrass and ginger at RAAL Griya Asih Lawang.Methods: Using a case study design with nursing care. The subjects of this research were 3 elderly gout patients with chronic pain nursing problems for 3 days, with pain measurement using the Visual Analog Scale (VAS) and SLKI. and the targeted outcome criteria include the ability to complete activities, complaints of pain, protective attitudes, grimacing, restlessness and difficulty sleeping. The instrument used was the UNITRI gerontic nursing care format. Data was analyzed using the SMART method (Specific, Measurable, Achievable, Realistic, Time).Results: From the actions carried out on the three patients for 3 days, it was found that the chronic pain nursing problem in 3 patients was partially resolved with the following criteria: ability to complete activities increased, pain complaints decreased, protective attitude decreased, grimaces decreased, anxiety decreased, difficulty sleeping decreased.Conclusion: Due to limited time in conducting this research, which was only carried out for 3 days, it could affect the results of warm compresses using lemongrass and ginger which could only partially reduce pain complaints.Keywords: chronic pain, gout, warm water compress using lemongrass and ginger.

Uric acid formation is driven by crosstalk between skeletal muscle and other cell types.

Hyperuricemia is implicated in numerous pathologies, but the mechanisms underlying uric acid production are poorly understood. Using a combination of mouse studies, cell culture studies, and human serum samples, we sought to determine the cellular source of uric acid. In mice, fasting and glucocorticoid treatment increased serum uric acid and uric acid release from ex vivo-incubated skeletal muscle. In vitro, glucocorticoids and the transcription factor FoxO3 increased purine nucleotide degradation and purine release from differentiated muscle cells, which coincided with the transcriptional upregulation of AMP deaminase 3, a rate-limiting enzyme in adenine nucleotide degradation. Heavy isotope tracing during coculture experiments revealed that oxidation of muscle purines to uric acid required their transfer from muscle cells to a cell type that expresses xanthine oxidoreductase, such as endothelial cells. Last, in healthy women, matched for age and body composition, serum uric acid was greater in individuals scoring below average on standard physical function assessments. Together, these studies reveal skeletal muscle purine degradation is an underlying driver of uric acid production, with the final step of uric acid production occurring primarily in a nonmuscle cell type. This suggests that skeletal muscle fiber purine degradation may represent a therapeutic target to reduce serum uric acid and treat numerous pathologies.

Integrated Functions of Cardiac Energetics, Mechanics, and Purine Nucleotide Metabolism.

Purine nucleotides play central roles in energy metabolism in the heart. Most fundamentally, the free energy of hydrolysis of the adenine nucleotide adenosine triphosphate (ATP) provides the thermodynamic driving force for numerous cellular processes including the actin-myosin crossbridge cycle. Perturbations to ATP supply and/or demand in the myocardium lead to changes in the homeostatic balance between purine nucleotide synthesis, degradation, and salvage, potentially affecting myocardial energetics and, consequently, myocardial mechanics. Indeed, both acute myocardial ischemia and decompensatory remodeling of the myocardium in heart failure are associated with depletion of myocardial adenine nucleotides and with impaired myocardial mechanical function. Yet there remain gaps in the understanding of mechanistic links between adenine nucleotide degradation and contractile dysfunction in heart disease. The scope of this article is to: (i) review current knowledge of the pathways of purine nucleotide depletion and salvage in acute ischemia and in chronic heart disease; (ii) review hypothesized mechanisms linking myocardial mechanics and energetics with myocardial adenine nucleotide regulation; and (iii) highlight potential targets for treating myocardial metabolic and mechanical dysfunction associated with these pathways. It is hypothesized that an imbalance in the degradation, salvage, and synthesis of adenine nucleotides leads to a net loss of adenine nucleotides in both acute ischemia and under chronic high-demand conditions associated with the development of heart failure. This reduction in adenine nucleotide levels results in reduced myocardial ATP and increased myocardial inorganic phosphate. Both of these changes have the potential to directly impact tension development and mechanical work at the cellular level. © 2024 American Physiological Society. Compr Physiol 14:5345-5369, 2024.

Unique Gut Microbiome Signatures among Adult Patients with Moderate to Severe Atopic Dermatitis in Southern Chinese.

Imbalance of the immune system caused by alterations of the gut microbiome is considered to be a critical factor in the pathogenesis of infant eczema, but the exact role of the gut microbiome in adult atopic dermatitis (AD) patients remains to be clarified. To investigate the differences of the gut microbiome between adult AD patients and healthy individuals, stool samples of 234 adults, containing 104 AD patients and 130 healthy subjects, were collected for 16S rRNA gene amplicon. Altered structure and metabolic dysfunctions of the gut microbiome were identified in adult AD patients. Our results illustrated that the adult AD patients were more likely to have allergies, particularly non-food allergies. In addition, the gut microbiome composition of the AD and normal groups were considerably different. Moreover, Romboutsia and Clostridi-um_sensu_stricto_1 was enriched in the normal group, whereas Blautia, Butyricicoccus, Lachnoclostridium, Eubacterium_hallii_group, Erysi-pelatoclostridium, Megasphaera, Oscillibacter, and Flavonifractor dominated in the AD group. Additionally, purine nucleotide degradation pathways were significantly enriched in the AD group, and the enrichment of proteinogenic amino acid biosynthesis pathways was found in the normal group. This study provides insights into new therapeutic strategies targeting the gut microbiome for AD and evidence for the involvement of the gut-skin axis in AD patients.

Increased activity of enzymes involved in purine metabolism as one of the factors of rectal cancer pathogenesis

Aim: to study changes in the activities of purine nucleotide degradation enzymes – adenosine deaminase (ADA) and xanthine oxidase (XO) in patients with rectum cancer (RC).Material and Methods. The activity of purine nucleotide degradation enzymes was studied in blood plasma and tissue homogenates: tumor tissue and normal rectal mucosa in 70 patients with stage I–IV RC. The histological type of RC was adenocarcinoma. The levels of ADA and XO activities were measured using spectrophotometry.Results. The activity of ADA and XO in blood serum of RC patients was significantly higher than that of healthy people. A significant increase in the activity of ADA and XO in tumor tissue compared to normal tissue was also found. The relationship between the activities of the enzymes of purine catabolism in blood plasma and tissues were revealed. An increase in purine catabolism depending on the stage of RC was found.Conclusion. The increased ADA and XO activities indicated the enhanced purine catabolism not only in malignant transformation, but also in tumor progression.

Mouse tissue harvest-induced hypoxia rapidly alters the in vivo metabolome, between-genotype metabolite level differences, and 13C-tracing enrichments

ObjectiveMetabolomics as an approach to solve biological problems is exponentially increasing in use. Thus, this a pivotal time for the adoption of best practices. It is well known that disrupted tissue oxygen supply rapidly alters cellular energy charge. However, the speed and extent to which delayed mouse tissue freezing after dissection alters the broad metabolome is not well described. Furthermore, how tissue genotype may modulate such metabolomic drift and the degree to which traced 13C-isotopologue distributions may change have not been addressed. MethodsBy combined liquid chromatography (LC)- and gas chromatography (GC)-mass spectrometry (MS), we measured how levels of 255 mouse liver metabolites changed following 30-second, 1-minute, 3-minute, and 10-minute freezing delays. We then performed test-of-concept delay-to-freeze experiments evaluating broad metabolomic drift in mouse heart and skeletal muscle, differential metabolomic change between wildtype (WT) and mitochondrial pyruvate carrier (MPC) knockout mouse livers, and shifts in 13C-isotopologue abundances and enrichments traced from 13C-labled glucose into mouse liver. ResultsOur data demonstrate that delayed mouse tissue freezing after dissection leads to rapid hypoxia-driven remodeling of the broad metabolome, induction of both false-negative and false-positive between-genotype differences, and restructuring of 13C-isotopologue distributions. Notably, we show that increased purine nucleotide degradation products are an especially high dynamic range marker of delayed liver and heart freezing. ConclusionsOur findings provide a previously absent, systematic illustration of the extensive, multi-domain metabolomic changes occurring within the early minutes of delayed tissue freezing. They also provide a novel, detailed resource of mouse liver ex vivo, hypoxic metabolomic remodeling.

In silico-guided metabolic engineering of Bacillus subtilis for efficient biosynthesis of purine nucleosides by blocking the key backflow nodes

BackgroundPurine nucleosides play essential roles in cellular physiological processes and have a wide range of applications in the fields of antitumor/antiviral drugs and food. However, microbial overproduction of purine nucleosides by de novo metabolic engineering remains a great challenge due to their strict and complex regulatory machinery involved in biosynthetic pathways.ResultsIn this study, we designed an in silico-guided strategy for overproducing purine nucleosides based on a genome-scale metabolic network model in Bacillus subtilis. The metabolic flux was analyzed to predict two key backflow nodes, Drm (purine nucleotides toward PPP) and YwjH (PPP–EMP), to resolve the competitive relationship between biomass and purine nucleotide synthesis. In terms of the purine synthesis pathway, the first backflow node Drm was inactivated to block the degradation of purine nucleotides, which greatly increased the inosine production to 13.98–14.47 g/L without affecting cell growth. Furthermore, releasing feedback inhibition of the purine operon by promoter replacement enhanced the accumulation of purine nucleotides. In terms of the central carbon metabolic pathways, the deletion of the second backflow node YwjH and overexpression of Zwf were combined to increase inosine production to 22.01 ± 1.18 g/L by enhancing the metabolic flow of PPP. By switching on the flux node of the glucose-6-phosphate to PPP or EMP, the final inosine engineered strain produced up to 25.81 ± 1.23 g/L inosine by a pgi-based metabolic switch with a yield of 0.126 mol/mol glucose, a productivity of 0.358 g/L/h and a synthesis rate of 0.088 mmol/gDW/h, representing the highest yield in de novo engineered inosine bacteria. Under the guidance of this in silico-designed strategy, a general chassis bacterium was generated, for the first time, to efficiently synthesize inosine, adenosine, guanosine, IMP and GMP, which provides sufficient precursors for the synthesis of various purine intermediates.ConclusionsOur study reveals that in silico-guided metabolic engineering successfully optimized the purine synthesis pathway by exploring efficient targets, which could be applied as a superior strategy for efficient biosynthesis of biotechnological products.

Umami-induced obesity and metabolic syndrome is mediated by nucleotide degradation and uric acid generation.

Umami refers to the savoury taste that is mediated by monosodium glutamate (MSG) and enhanced by inosine monophosphate and other nucleotides. Umami foods have been suggested to increase the risk for obesity and metabolic syndrome but the mechanism is not understood. Here we show that MSG induces obesity, hypothalamic inflammation and central leptin resistance in male mice through the induction of AMP deaminase 2 and purine degradation. Mice lacking AMP deaminase 2 in both hepatocytes and neurons are protected from MSG-induced metabolic syndrome. This protection can be overcome by supplementation with inosine monophosphate, most probably owing to its degradation to uric acid as the effect can be blocked with allopurinol. Thus, umami foods induce obesity and metabolic syndrome by engaging the same purine nucleotide degradation pathway that is also activated by fructose and salt consumption. We suggest that the three tastes-sweet, salt and umami-developed to encourage food intake to facilitate energy storage and survival but drive obesity and diabetes in the setting of excess intake through similar mechanisms.

Sensing soluble uric acid by Naip1-Nlrp3 platform

Uric acid (UA), a product of purine nucleotide degradation able to initiate an immune response, represents a breakpoint in the evolutionary history of humans, when uricase, the enzyme required for UA cleavage, was lost. Despite being inert in human cells, UA in its soluble form (sUA) can increase the level of interleukin-1β (IL-1β) in murine macrophages. We, therefore, hypothesized that the recognition of sUA is achieved by the Naip1-Nlrp3 inflammasome platform. Through structural modelling predictions and transcriptome and functional analyses, we found that murine Naip1 expression in human macrophages induces IL-1β expression, fatty acid production and an inflammation-related response upon sUA stimulation, a process reversed by the pharmacological and genetic inhibition of Nlrp3. Moreover, molecular interaction experiments showed that Naip1 directly recognizes sUA. Accordingly, Naip may be the sUA receptor lost through the human evolutionary process, and a better understanding of its recognition may lead to novel anti-hyperuricaemia therapies.

Muscle Metabolome Profiles in Woody Breast-(un)Affected Broilers: Effects of Quantum Blue Phytase-Enriched Diet.

Woody breast (WB) myopathy is significantly impacting modern broilers and is imposing a huge economic burden on the poultry industry worldwide. Yet, its etiology is not fully defined. In a previous study, we have shown that hypoxia and the activation of its upstream mediators (AKT/PI3K/mTOR) played a key role in WB myopathy, and supplementation of quantum blue (QB) can help to reduce WB severity via modulation of hypoxia-related pathways. To gain further insights, we undertook here a metabolomics approach to identify key metabolite signatures and outline their most enriched biological functions. Ultra performance liquid chromatography coupled with high resolution mass spectrometry (UPLC–HRMS) identified a total of 108 known metabolites. Of these, mean intensity differences at P < 0.05 were found in 60 metabolites with 42 higher and 18 lower in WB-affected compared to unaffected muscles. Multivariate analysis and Partial Least Squares Discriminant analysis (PLS-DA) scores plot displayed different clusters when comparing metabolites profile from affected and unaffected tissues and from moderate (MOD) and severe (SEV) WB muscles indicating that unique metabolite profiles are present for the WB-affected and unaffected muscles. To gain biologically related molecule networks, a stringent pathway analyses was conducted using IPA knowledge-base. The top 10 canonical pathways generated, using a fold-change −1.5 and 1.5 cutoff, with the 50 differentially abundant-metabolites were purine nucleotide degradation and de novo biosynthesis, sirtuin signaling pathway, citrulline-nitric oxide cycle, salvage pathways of pyrimidine DNA, IL-1 signaling, iNOS, Angiogenesis, PI3K/AKT signaling, and oxidative phosphorylation. The top altered bio-functions in term of molecular and cellular functions in WB-affected tissues included cellular development, cellular growth and proliferation, cellular death and survival, small molecular biochemistry, inflammatory response, free radical scavenging, cell signaling and cell-to-cell interaction, cell cycles, and lipid, carbohydrate, amino acid, and nucleic acid metabolisms. The top disorder functions identified were organismal injury and abnormalities, cancer, skeletal and muscular disorders, connective tissue disorders, and inflammatory diseases. Breast tissues from birds fed with high dose (2,000 FTU) of QB phytase exhibited 22 metabolites with significantly different levels compared to the control group with a clear cluster using PLS-DA analysis. Of these 22 metabolites, 9 were differentially abundant between WB-affected and unaffected muscles. Taken together, this study determined many metabolic signatures and disordered pathways, which could be regarded as new routes for discovering potential mechanisms of WB myopathy.

Abstract MP121: Deleting the 2-oxoglutarate- and Iron-dependent Prolyl Hydroxylase Ogfod1 Alters Purine Nucleotide Regulation and is Cardioprotective

Prolyl hydroxylation is a post-translational modification that regulates protein stability, turnover, and activity. The proteins that catalyze prolyl hydroxylation belong to the 2-oxoglutarate- and iron-dependent oxygenase family of enzymes. A newly-described member of this family is 2-oxoglutarate- and iron-dependent oxygenase domain containing protein 1 (Ogfod1), which catalyzes prolyl hydroxylation of the ribosomal protein s23 (Rps23). To investigate the cardiovascular function of Ogfod1, we isolated hearts from 5 Ogfod1 -WT and 5 Ogfod1 -KO mice and used Liquid Chromatography and Tandem Mass Spectrometry (LC-MS/MS) to identify proteomic changes. Ingenuity Pathway Analysis (IPA) identified “Purine Nucleotides Degradation II (Aerobic)” ( P = 0.00017) to be one of the most significantly-enriched pathways. We then did metabolomics and found that Inosine 5’-monophosphate (IMP) was 3.5x higher in Ogfod1 -KO hearts ( P = 0.011), further supporting a role for Ogfod1 in regulating purine nucleotide metabolism. Recent evidence has shown that altering purine nucleotide degradation protects against diet-induced obesity and insulin resistance, so we tested this hypothesis in Ogfod1 -KO mice by feeding them high-fat diets. Ogfod1 ablation protects against high-fat diet-induced obesity and insulin resistance. Altering purine nucleotide degradation has also been shown to be protective against cardiac injury, so we tested the hypothesis that Ogfod1 loss protects the heart from ischemia-reperfusion (I/R) injury by subjecting perfused hearts from 6 Ogfod1 -WT and 6 Ogfod1 -KO mice to ischemia and reperfusion and assessed tissue death. We found a 37% decrease in infarct size in Ogfod1 -KO hearts (56% in Ogfod1 -WT and 35% in Ogfod1 -KO, P = 0.0003). In a separate set of experiments, we treated Ogofd1 -KO mice with isoproterenol to induce hypertrophy, and Ogfod1 -KO hearts showed protection against hypertrophic remodeling. Interestingly, OGFOD1 transcripts were up-regulated in human heart failure, indicating a potential role for OGFOD1 in the human failing heart. Altogether, these data show that Ogfod1 deletion alters the myocardial proteome and myocardial metabolism and protects against obesity, insulin sensitivity, I/R injury, and hypertrophy.

The role of uric acid in inflammasome-mediated kidney injury.

Uric acid is produced after purine nucleotide degradation, upon xanthine oxidase catalytic action. In the evolutionary process, humans lost uricase, an enzyme that converts uric acid into allantoin, resulting in increased serum uric acid levels that may vary according to dietary ingestion, pathological conditions, and other factors. Despite the controversy over the inflammatory role of uric acid in its soluble form, crystals of uric acid are able to activate the NLRP3 inflammasome in different tissues. Uric acid, therefore, triggers hyperuricemic-related disease such as gout, metabolic syndrome, and kidney injuries. The present review provides an overview on the role of uric acid in the inflammasome-mediated kidney damage. Hyperuricemia is present in 20-35% of patients with chronic kidney disease. However, whether this increased circulating uric acid is a risk factor or just a biomarker of renal and cardiovascular injuries has become a topic of intense discussion. Despite these conflicting views, several studies support the idea that hyperuricemia is indeed a cause of progression of kidney disease, with a putative role for soluble uric acid in activating renal NLRP3 inflammasome, in reprograming renal and immune cell metabolism and, therefore, in promoting kidney inflammation/injury. Therapies aiming to decrease uric acid levels prevent renal NLRP3 inflammasome activation and exert renoprotective effects in experimental kidney diseases. However, further clinical studies are needed to investigate whether reduced circulating uric acid can also inhibit the inflammasome and be beneficial in human conditions.

Purine metabolism in the light of aerobic and anaerobic capacity of female boxers

The aim of the work was to assess the intensity of purine nucleotide degradation during maximum physical exercise. 5 elite female boxers were the subject of the study. Each of them underwent two exercise stress tests in order to evaluate the level of VO2peak and the level of anaerobic capacity during a Wingate test. The study involved collecting capillary and venous blood samples at rest and after the exercise test to determine the Acid-Base Balance (ABB), concentration of lactic acid (LA) and purine metabolism nucleotides. The average value of VO2peak was 40.92 (SD = 4.087) ml/kg/min, the average anaerobic capacity Ppeak was 7.57 (SD = 0.380) Watt/kg. The workload resulted in significant changes in the level of ABB and LA after both of the exercise stress tests (p < 0.001). Concentrations of hypoxanthine (Hx), xanthine (X) and uric acid (UA) in the blood increased significantly after the Wingate test (p < 0.05). The level of plasma purine nucleotides at rest and after standard exercise may be a useful tool for monitoring the adaptation of energetic processes in different training phases and support the overload diagnosis.

Degradation of brown adipocyte purine nucleotides regulates uncoupling protein 1 activity

ObjectiveNon-shivering thermogenesis in mammalian brown adipose tissue depends on thermogenic uncoupling protein 1. Its activity is triggered by free fatty acids while purine nucleotides mediate inhibition. During activation, it is thought that free fatty acids overcome purine-mediated inhibition. We measured the cellular concentration and the release of purine nucleotide metabolites to uncover a possible role of purine nucleotide degradation in uncoupling protein 1 activation. MethodsWith mass spectrometry, purine nucleotide metabolites were quantified in cellular homogenates and supernatants of cultured primary brown adipocytes. We also determined oxygen consumption in response to a β-adrenergic agonist. ResultsUpon adrenergic activation, brown adipocytes decreased the intracellular concentration of inhibitory nucleotides (ATP, ADP, GTP and GDP) and released the respective degradation products. At the same time, an increase in cellular calcium occurred. None of these phenomena occurred in white adipocytes or myotubes. The brown adipocyte expression of enzymes implicated in purine metabolic remodeling is altered upon cold exposure. Pharmacological and genetic interference of purine metabolism altered uncoupling protein 1 mediated uncoupled respiration. ConclusionAdrenergic stimulation of brown adipocytes lowers the intracellular concentration of purine nucleotides, thereby contributing to uncoupling protein 1 activation.

Periodic variation in bile acids controls circadian changes in uric acid via regulation of xanthine oxidase by the orphan nuclear receptor PPARα

Xanthine oxidase (XOD), also known as xanthine dehydrogenase, is a rate-limiting enzyme in purine nucleotide degradation, which produces uric acid. Uric acid concentrations in the blood and liver exhibit circadian oscillations in both humans and rodents; however, the underlying mechanisms remain unclear. Here, we demonstrate that XOD expression and enzymatic activity exhibit circadian oscillations in the mouse liver. We found that the orphan nuclear receptor peroxisome proliferator-activated receptor-α (PPARα) transcriptionally activated the mouse XOD gene and that bile acids suppressed XOD transactivation. The synthesis of bile acids is known to be under the control of the circadian clock, and we observed that the time-dependent accumulation of bile acids in hepatic cells interfered with the recruitment of the co-transcriptional activator p300 to PPARα, thereby repressing XOD expression. This time-dependent suppression of PPARα-mediated transactivation by bile acids caused an oscillation in the hepatic expression of XOD, which, in turn, led to circadian alterations in uric acid production. Finally, we also demonstrated that the anti-hyperuricemic effect of the XOD inhibitor febuxostat was enhanced by administering it at the time of day before hepatic XOD activity increased. These results suggest an underlying mechanism for the circadian alterations in uric acid production and also underscore the importance of selecting an appropriate time of day for administering XOD inhibitors.

Gout as a consequence of bone healing: A diagnostic dilemma

Diagnosis of acute gout remains a diagnostic challenge if associated with trauma, and may easily be mistaken as cellulitis or septic arthritis. Gout is an inflammatory arthritis that is triggered by the deposition of sodium urate crystals within the joints and soft tissues, and is frequently associated with hyperuricemia. Hyperuricemia may arise in a wide range of clinical situations that cause overproduction or under-excretion of uric acid, or a combination of both. As uric acid is the ultimate breakdown product of purine nucleotide degradation in humans, any increase in purine production due to accelerated cell turnover may precipitate an acute attack of gout. Gout may be precipitated by conditions such a trauma, surgery, diuretic therapy, or ethanol intake. All predisposed individuals such as those with hypreuricemia, hypothyroid etc. with trauma and bone fractures should be observed for precipitation of acute gouty arthritis. Bone healing after a fracture may also lead to acute gout. Healing of a fractured bone, through multiple mechanisms, can precipitate acute gout, particularly in the presence of certain predisposing factors such as hypothyroidism, pre-existing hyperuricemia or tissue hypoxia. Acute inflammation and pain, if resistant to non-steroidal anti-inflammatory drugs, may necessitate treatment with colchicine.

The Potential Biomarkers to Identify the Development of Steatosis in Hyperuricemia.

Hyperuricemia (HU) often progresses to combine with non-alcoholic fatty liver disease (NAFLD) in the clinical scenario, which further exacerbates metabolic disorders; early detection of biomarkers, if obtained during the HU progression, may be beneficial for preventing its combination with NAFLD. This study aimed to decipher the biomarkers and mechanisms of the development of steatosis in HU. Four groups of subjects undergoing health screening, including healthy subjects, subjects with HU, subjects with HU combined with NAFLD (HU+NAFLD) and subjects with HU initially and then with HU+NAFLD one year later (HU→HU+NAFLD), were recruited in this study. The metabolic profiles of all subjects’ serum were analyzed by liquid chromatography quadruple time-of-flight mass spectrometry. The metabolomic data from subjects with HU and HU+NAFLD were compared, and the biomarkers for the progression from HU to HU+NAFLD were predicted. The metabolomic data from HU→HU+NAFLD subjects were collected for further verification. The results showed that the progression was associated with disturbances of phospholipase metabolism, purine nucleotide degradation and Liver X receptor/retinoic X receptor activation as characterized by up-regulated phosphatidic acid, cholesterol ester (18:0) and down-regulated inosine. These metabolic alterations may be at least partially responsible for the development of steatosis in HU. This study provides a new paradigm for better understanding and further prevention of disease progression.

Differential regulation of caffeine metabolism in Coffea arabica (Arabica) and Coffea canephora (Robusta).

Caffeine is a metabolite of great economic importance, especially in coffee, where it influences the sensorial and physiological impacts of the beverage. Caffeine metabolism in the Coffea species begins with the degradation of purine nucleotides through three specific N-methyltransferases: XMT, MXMT and DXMT. A comparative analysis was performed to clarify the molecular reasons behind differences in caffeine accumulation in two Coffea species, namely Coffea arabica and Coffea canephora var. robusta. Three different genes encoding N-methyltransferase were amplified in the doubled haploid Coffea canephora: CcXMT1, CcMXMT1 and CcDXMT. Six genes were amplified in the haploid Coffea arabica: CaXMT1, CaXMT2, CaMXMT1, CaMXMT2, CaDXMT1, and CaDXMT2. A complete phylogenic analysis was performed to identify specific key amino acids defining enzymatic function for each protein identified. Furthermore, a quantitative gene-expression analysis was conducted on leaves and on maturing coffee beans, simultaneously analyzing caffeine content. In the different varieties analyzed, caffeine accumulation is higher in leaves than in the coffee bean maturation period, higher in Robusta than in Arabica. In Robusta, CcXMT1 and CcDXMT gene expressions are predominant and transcriptional activity is higher in leaves than in maturing beans, and is highly correlated to caffeine accumulation. In Arabica, the CaXMT1 expression level is high in leaves and CaDXMT2 as well to a lesser extent, while global transcriptional activity is weak during bean maturation, suggesting that the transcriptional control of caffeine-related genes differs within different organs and between Arabica and Robusta. These findings indicate that caffeine accumulation in Coffea species has been modulated by a combination of differential transcriptional regulation and genome evolution.Electronic supplementary materialThe online version of this article (doi:10.1007/s00425-014-2170-7) contains supplementary material, which is available to authorized users.

Purine nucleotides and their metabolites in patients with type 1 and 2 diabetes mellitus

We measured the erythrocyte levels of principal nucleotides (ATP, ADP, AMP, GTP, GDP, GMP, IMP), nucleosides (Ado, Guo, Ino) and Hyp with HPLC. Purine concentrations were determined in the erythrocytes of 36 type 1 and 40 type 2 diabetic patients. The increased dephosphorylation of adenine and guanine nucleotides, indicated by increased Ado, Ino, Guo and Hyp concentrations as the products of purine nucleotide degradation, suggests serious energy metabolism disruptions in diabetes. An increase in AMP, GMP, IMP concentrations, as well as a decrease in AEC and GEC values, points to significant alterations in erythrocyte purine nucleotide concentration.