Exercise in Glucose-6-Phosphate Dehydrogenase Deficiency: Harmful or Harmless? A Narrative Review

Evidence-based sports supplements: A redox analysis

Despite the overwhelming number of sports supplements on the market, only seven are currently recognized as effective. Biological functions are largely regulated through redox reactions, yet no comprehensive analysis of the redox properties of these supplements has been compiled. Here, we analyze the redox characteristics of these seven supplements: bicarbonates, beta-alanine, caffeine, creatine, nitrates, carbohydrates, and proteins. Our findings suggest that all sports supplements exhibit some degree of redox activity. However, the precise physiological implications of these redox properties remain unclear. Future research, employing unconventional perspectives and methodologies, will reveal new redox pixels of the exercise physiology and sports nutrition picture.

Delineation of the role of G6PD in Alzheimer's disease and potential enhancement through microfluidic and nanoparticle approaches

Alzheimer's disease (AD) is a neurodegenerative pathologic entity characterized by the abnormal presence of tau and macromolecular Aβ deposition that leads to the degeneration or death of neurons. In addition to that, glucose-6-phosphate dehydrogenase (G6PD) has a multifaceted role in the process of AD development, where it can be used as both a marker and a target. G6PD activity is dysregulated due to its contribution to oxidative stress, neuroinflammation, and neuronal death. In this context, the current review presents a vivid depiction of recent findings on the relationship between AD progression and changes in the expression or activity of G6PD. The efficacy of the proposed G6PD-based therapeutics has been demonstrated in multiple studies using AD mouse models as representative animal model systems for cognitive decline and neurodegeneration associated with this disease. Innovative therapeutic insights are made for the boosting of G6PD activity via novel innovative nanotechnology and microfluidics tools in drug administration technology. Such approaches provide innovative methods of surpassing the blood-brain barrier, targeting step-by-step specific neural pathways, and overcoming biochemical disturbances that accompany AD. Using different nanoparticles loaded with G6DP to target specific organs, e.g., G6DP-loaded liposomes, enhances BBB penetration and brain distribution of G6DP. Many nanoparticles, which are used for different purposes, are briefly discussed in the paper. Such methods to mimic BBB on organs on-chip offer precise disease modeling and drug testing using microfluidic chips, requiring lower sample amounts and producing faster findings compared to conventional techniques. There are other contributions to microfluid in AD that are discussed briefly. However, there are some limitations accompanying microfluidics that need to be worked on to be used for AD. This study aims to bridge the gap in understanding AD with the synergistic use of promising technologies; microfluid and nanotechnology for future advancements.

Erythrocyte metabolism

Our aim is to present an updated overview of the erythrocyte metabolism highlighting its richness and complexity. We have manually collected and connected the available biochemical pathways and integrated them into a functional metabolic map. The focus of this map is on the main biochemical pathways consisting of glycolysis, the pentose phosphate pathway, redox metabolism, oxygen metabolism, purine/nucleoside metabolism, and membrane transport. Other recently emerging pathways are also curated, like the methionine salvage pathway, the glyoxalase system, carnitine metabolism, and the lands cycle, as well as remnants of the carboxylic acid metabolism. An additional goal of this review is to present the dynamics of erythrocyte metabolism, providing key numbers used to perform basic quantitative analyses. By synthesizing experimental and computational data, we conclude that glycolysis, pentose phosphate pathway, and redox metabolism are the foundations of erythrocyte metabolism. Additionally, the erythrocyte can sense oxygen levels and oxidative stress adjusting its mechanics, metabolism, and function. In conclusion, fine-tuning of erythrocyte metabolism controls one of the most important biological processes, that is, oxygen loading, transport, and delivery.

The Association between Glucose 6-Phosphate Dehydrogenase Deficiency and Attention Deficit/Hyperactivity Disorder

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, impacting 4.9% of the population and more prevalent in Mediterranean communities, is a common enzymopathy with potential relevance to Attention Deficit/Hyperactivity Disorder (ADHD). This study investigated this association.

METHODS

The clinical characteristics of 7473 G6PD-deficient patients and 29,892 matched case-controls (selected at a 1:4 ratio) from a cohort of 1,031,354 within the Leumit Health Services database were analyzed using Fisher's exact test for categorical variables and the Mann-Whitney U test for continuous variables.

RESULTS

In total, 68.7% were male. The mean duration of follow-up was 14.3 ± 6.2 years at a mean age of 29.2 ± 22.3 years. G6PD deficiency was associated with an increased risk of being diagnosed with ADHD (Odds Ratio (OR) = 1.16 [95% CI, 1.08-1.25], p < 0.001), seeking care from adult neurologists (OR = 1.30 [95% CI, 1.22-1.38], p < 0.001), and consulting adult psychiatrists (OR = 1.12 [95% CI, 1.01-1.24], p = 0.048). The use of stimulant medications among G6PD-deficient individuals was 17% higher for the methylphenidate class of drugs (OR = 1.17 [95% CI, 1.08, 1.27], p < 0.001), and there was a 16% elevated risk for amphetamine use (OR = 1.16 [95% CI, 1.03, 1.37], p = 0.047).

CONCLUSIONS

G6PD deficiency signals an increased risk of ADHD diagnosis, more severe presentations of ADHD and a greater need for psychiatric medications to treat ADHD.

Glucose 6-P Dehydrogenase—An Antioxidant Enzyme with Regulatory Functions in Skeletal Muscle during Exercise

Hypomorphic Glucose 6-P dehydrogenase (G6PD) alleles, which cause G6PD deficiency, affect around one in twenty people worldwide. The high incidence of G6PD deficiency may reflect an evolutionary adaptation to the widespread prevalence of malaria, as G6PD-deficient red blood cells (RBCs) are hostile to the malaria parasites that infect humans. Although medical interest in this enzyme deficiency has been mainly focused on RBCs, more recent evidence suggests that there are broader implications for G6PD deficiency in health, including in skeletal muscle diseases. G6PD catalyzes the rate-limiting step in the pentose phosphate pathway (PPP), which provides the precursors of nucleotide synthesis for DNA replication as well as reduced nicotinamide adenine dinucleotide phosphate (NADPH). NADPH is involved in the detoxification of cellular reactive oxygen species (ROS) and de novo lipid synthesis. An association between increased PPP activity and the stimulation of cell growth has been reported in different tissues including the skeletal muscle, liver, and kidney. PPP activity is increased in skeletal muscle during embryogenesis, denervation, ischemia, mechanical overload, the injection of myonecrotic agents, and physical exercise. In fact, the highest relative increase in the activity of skeletal muscle enzymes after one bout of exhaustive exercise is that of G6PD, suggesting that the activation of the PPP occurs in skeletal muscle to provide substrates for muscle repair. The age-associated loss in muscle mass and strength leads to a decrease in G6PD activity and protein content in skeletal muscle. G6PD overexpression in Drosophila Melanogaster and mice protects against metabolic stress, oxidative damage, and age-associated functional decline, and results in an extended median lifespan. This review discusses whether the well-known positive effects of exercise training in skeletal muscle are mediated through an increase in G6PD.

In-depth characterization revealed polymer type and chemical content specific effects of microplastic on Dreissena bugensis

In aquatic ecosystems, filter feeders like mussels are particularly vulnerable to microplastics (MP). However, little is known about how the polymer type and the associated properties (like additives or remaining monomers) of MP impact organisms, as the predominant type of MP used for effect studies on the organismic level are micron grade polystyrene spheres, without considering their chemical composition. Therefore, we exposed the freshwater mussel Dreissena bugensis (D. bugensis) to in-depth characterized fragments in the same concentration and size range (20-120 µm): recycled polyethylene terephthalate from drinking bottles, polyamide, polystyrene, polylactic acid, and mussel shell fragments as natural particle control. Real-time valvometry, used to study behavioral responses via the movement of the mussels' valves, showed that mussels cannot distinguish between natural and MP particles, and therefore do not cease their filtration, as when exposed to dissolved pollutants. This unintentional ingestion led to polymer type-dependent adverse effects (activity of antioxidant enzymes and proteomic alterations), related to chemicals and residual monomers found in MP. Overall, recycled PET elicited the strongest negative effects, likely caused by anthranilamide, anthranilonitrile and butylated hydroxytoluene, contained in the fragments, which are toxic to aquatic organisms. As PET is among the most abundant MP in the environment, sublethal effects may gradually manifest at the population level, leading to irreversible ecosystem changes.

The redox signal: A physiological perspective

A signal in biology is any kind of coded message sent from one place in an organism to another place. Biology is rich in claims that reactive oxygen and nitrogen species transmit signals. Therefore, we define a "redox signal as an increase/decrease in the level of reactive species". First, as in most biology disciplines, to analyze a redox signal you need first to deconstruct it. The essential components that constitute a redox signal and should be characterized are: (i) the reactivity of the specific reactive species, (ii) the magnitude of change, (iii) the temporal pattern of change, and (iv) the antioxidant condition. Second, to be able to translate the physiological fate of a redox signal you need to apply novel and bioplausible methodological strategies. Important considerations that should be taken into account when designing an experiment is to (i) assure that redox and physiological measurements are at the same or similar level of biological organization and (ii) focus on molecules that are at the highest level of the redox hierarchy. Third, to reconstruct the redox signal and make sense of the chaotic nature of redox processes, it is essential to apply mathematical and computational modeling. The aim of the present study was to collectively present, for the first time, those elements that essentially affect the redox signal as well as to emphasize that the deconstructing, decoding and reconstructing of a redox signal should be acknowledged as central to design better studies and to advance our understanding on its physiological effects.

Antixoxidant Supplements versus Health Benefits of Brief/Intermittent Exposure to Potentially Toxic Physical or Chemical Agents

Although antioxidants can act locally to react with an oxidant, oral administration of "antioxidants" is quite useless in treating oxidative stress in tissues. Furthermore, it does not make sense to consider a vitamin as an antioxidant, but vitamin B3 leads to the in vivo formation of compounds that are essential for reducing this stress. A rigorous treatment of the subject indicates that to deal with oxidative stress, the most direct approach is to enhance the innate antioxidant mechanisms. The question is whether this is possible through daily activities. Diets can contain the necessary components for these mechanisms or may induce the expression of the genes involved in them. Another possibility is that pro-oxidant molecules in food increase the sensitivity and power of the detoxification pathways. This option is based on well-known DNA repair mechanisms after exposure to radiation (even from the Sun), or strong evidence of induction of antioxidant capacity after exposure to powerful pro-oxidants such as H₂O₂. More experimental work is required to test whether some molecules in food can increase the expression of antioxidant enzymes and/or improve antioxidant mechanisms. Identifying effective molecules to achieve such antioxidant power is critical to the food and nutraceutical industries. The potential of diet-based interventions to combat oxidative stress must be viewed from a new perspective.

Aspirin Therapy in Cardiovascular Disease with Glucose-6-Phosphate Dehydrogenase Deficiency, Safe or Not?

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect, which may present as acute hemolysis, neonatal jaundice, or chronic hemolysis. Ingestion of fava beans, as well as infection and certain drugs, are the most typical causes of acute hemolysis in people with G6PD deficiency. Aspirin, the cornerstone in current therapies for the prevention of cardiovascular disease (CVD), is occasionally reported to induce acute hemolysis in G6PD-deficient individuals. G6PD deficiency is typically asymptomatic and many CVD patients with this enzyme defect start to take long-term aspirin therapy without G6PD activity examination; however, no consensus on the safety of aspirin in this population has been reached. A few studies have reported on this issue and produced contradictory results. In this review, we discuss the possible mechanisms of aspirin-induced hemolysis, and summarize clinical evidence regarding the safety of aspirin in subjects with G6PD deficiency.

Rasburicase-Induced Methemoglobinemia

Methemoglobinemia occurs as iron in heme is oxidized to its ferric state, resulting in a decreased ability of hemoglobin to bind and release oxygen. Rasburicase is a recombinant urate-oxidase enzyme used in the prevention of tumor lysis syndrome. Methemoglobinemia can occur as a rare complication of treatment with rasburicase, primarily in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Methylene blue, an agent used for treating methemoglobinemia, should be avoided in patients with G6PD deficiency. In patients with G6PD deficiency, methylene blue is inadequately reduced to its active form, which then causes the methylene blue to further the oxidize the hemoglobin to methemoglobin that can result in hemolysis.

[The activity of NAD- and NAD(P)-dependent dehydrogenases in lymphocytes of peripheral blood in Graves' disease]

BACKGROUND

The regulatory effect of thyroid hormones on the metabolism of the immune system cells (activation of oxidative processes, separation of oxidative phosphorylation and increased protein synthesis) depends on their number. Changes in the activity of intracellular enzymes in Graves&rsquo; disease (GD) can determine the mechanisms of maintaining autoimmune inflammation in relapse of the disease. The exact role of NAD(P)-dependent dehydrogenases in the development and maintenance of immune response in GD is still poorly investigated.

AIMS

To study the activity of NAD(P)-dependent dehydrogenases in lymphocytes of peripheral blood in patients with manifestation and relapse of GD to clarify the mechanisms of development and progression of the autoimmune process.

METHODS

A single-center, cohort, prospective, continuous, observational, open-label, controlled trial was conducted to evaluate the lymphocytes NAD(P)-dependent activity in 151 women with GD and hyperthyroidism, mean age 40.7&plusmn;13.2, 52 (37.14%), who were on follow-up at the endocrinology center of Krasnoyarsk Regional clinical hospital from 2016 to 2019. The NAD(P)-dependent dehydrogenases activity measured using biochemiluminescence method.

RESULTS

In patients with newly diagnosed of GD, relative to the control values and levels detected in relapse group we observe the increase of G6PDH and decrease of NADH-LDH. In GD relapse group compare to the control range in blood lymphocytes decreases the activity of LDH and NAD(P)-ICDH. In patients with newly diagnosed GD, two positive сorrelation were found: between fT3 level and MDG activity (r=0.90, p=0.037), and between fT4 level and NAD(P)-ICDH activity (r=0.82, p=0.007). In patients with relapse of GD positive relationships between the concentration of TSH and the activity of LDH (r=0.73, p=0.039), and MDH (r=0.93, p=0.002), as well as in a pair of fT4 and NADGDH (r=0.70, p=0.036) were revealed.

CONCLUSION

The established differences in the activity of NAD(P)-dependent dehydrogenases in peripheral blood lymphocytes in patients with manifestation and relapse of GD can reflect in the first case the response of immune cells to a functional-regulatory signal with the development of hyperthyroidism, and in the second case, adaptive changes with the progression of autoimmune process.

A Translational In Vivo and In Vitro Metabolomic Study Reveals Altered Metabolic Pathways in Red Blood Cells of Type 2 Diabetes

Clinical parameters used in type 2 diabetes mellitus (T2D) diagnosis and monitoring such as glycosylated haemoglobin (HbA1c) are often unable to capture important information related to diabetic control and chronic complications. In order to search for additional biomarkers, we performed a pilot study comparing T2D patients with healthy controls matched by age, gender, and weight. By using ¹H-nuclear magnetic resonance (NMR) based metabolomics profiling of red blood cells (RBCs), we found that the metabolic signature of RBCs in T2D subjects differed significantly from non-diabetic controls. Affected metabolites included glutathione, 2,3-bisphophoglycerate, inosinic acid, lactate, 6-phosphogluconate, creatine and adenosine triphosphate (ATP) and several amino acids such as leucine, glycine, alanine, lysine, aspartate, phenylalanine and tyrosine. These results were validated by an independent cohort of T2D and control patients. An analysis of the pathways in which these metabolites were involved showed that energetic and redox metabolism in RBCs were altered in T2D, as well as metabolites transported by RBCs. Taken together, our results revealed that the metabolic profile of RBCs can discriminate healthy controls from T2D patients. Further research is needed to determine whether metabolic fingerprint in RBC could be useful to complement the information obtained from HbA1c and glycemic variability as well as its potential role in the diabetes management.

Severe Rhabdomyolysis in Glucose-6-Phosphate Dehydrogenase Deficiency

Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is an X-linked genetic disorder associated with intravascular hemolysis. Rhabdomyolysis with myoglobinuria in a patient with G6PD deficiency is a very rare manifestation, in fact, to the best of our knowledge, only a few case reports have been published in the literature to date. Herein, we report an unusual presentation of a 33-year-old male with G6PD deficiency with multiple episodes of severe rhabdomyolysis with no significant concurrent hemolysis. This case supports the hypothesis that rhabdomyolysis may be a rare manifestation of G6PD deficiency, though the exact causation still remains unclear.