Muscle glucose-6-phosphate dehydrogenase deficiency

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.

Management of Athletes With G6PD Deficiency: Does Missing an Enzyme Mean Missing More Games?

CONTEXT

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is likely the most prevalent enzyme deficiency on the planet, with an estimated 4.9% of people, or approximately 330 million individuals, across the globe affected by the disease. In the United States, 4% to 7% of the population is likely affected, but each year our nation's major sport leagues become more international. It is important for medical professionals who treat athletes to understand how this genetic condition can affect the athletes we are working with, especially because exercise in itself results in oxidative stress.

EVIDENCE ACQUISITION

PubMed was searched for relevant articles published from 1980 to 2018. The search terms G6PD, athletes, military, and sports were used.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Though some case reports suggest a potential impact on athlete safety and performance, controlled studies demonstrate limited impact of exercise on oxidative stress in G6PD-deficient individuals. The care of athletes with G6PD deficiency does not drastically differ from the care of athletes without this condition. Most of the medications and supplements that are regularly given to athletes should not negatively affect their health.

CONCLUSION

Although the care of athletes with G6PD deficiency is for the most part no different from the care of other athletes, there are certain situations (visiting areas where malaria is endemic) and medications for which it is important to recognize how your management should change. G6PD deficiency is not regularly screened for but could be considered if an athlete has known sickle cell disease or when traveling to areas where malaria is prevalent. Expanding our knowledge of G6PD deficiency will allow for better care of athletes.

Severe acute kidney injury owing to rhabdomyolysis and intravascular haemolysis in an 11-year-old child with G6PD deficiency

Glucose-6-phosphate dehydrogenase (G6PD) deficiency leading to acute intravascular haemolysis and acute kidney injury (AKI) is a known clinical presentation. However, there is a paucity of information regarding the occurrence of rhabdomyolysis and myoglobinuria in G6PD-deficient individuals, especially children. An 11-year-old south Indian Tamil girl presented with severe anaemia and anuric AKI following a short febrile illness. Investigations demonstrated evidence of intravascular haemolysis and rhabdomyolysis, and on histopathology myoglobin deposits (casts) were detected in the renal tubules. She was successfully managed with repeated sessions of haemodialysis and blood transfusions. Follow-up estimation of G6PD levels after 3 months confirmed severe G6PD deficiency (0.003 nkat/g haemoglobin). Although there are anecdotal reports of myoglobinuria in G6PD-deficient individuals, the occurrence of severe anuric AKI in this clinical setting has not been reported. It can be speculated that myoglobinuria (in addition to haemoglobinuria) can contribute towards jeopardising renal function in G6PD deficiency-related acute haemolytic crisis.

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

Objectives

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, theoretically, renders red blood cells (RBC) susceptible to oxidative stress. G6PD deficiency has also been found in other types of cells than RBC, such as leukocytes and myocytes, where an inefficient protection against oxidative stress may occur too. Glutathione (GSH), a significant antioxidant molecule, levels are lower in G6PD individuals, and theoretically, the probability of oxidative stress and haemolysis due to exercise in individuals with G6PD deficiency is increased, whereas dietary supplementation with antioxidants may have beneficial effects on various aspects of this enzymopathy.

Methods

A search of the available literature was conducted using the keywords glucose-6-phosphate dehydrogenase (G6PD), deficiency, disease, exercise, muscle, antioxidant, vitamin, supplement, and supplementation. The search was limited to publications in English, conducted on humans, and published until August 2018. After screening, only relevant articles were included.

Results

There is little evidence indicating that G6PD deficiency can cause perturbations in redox status, haemolysis, and clinical symptoms such as fatigability and myoglobinuria, especially after intense exercise, compared to individuals with normal enzyme levels.

Conclusions

Exercise could be used by G6PD-deficient individuals as a tool to improve their quality of life. However, there is a lack of training studies, and assessment of the effects of regular and systematic exercise in G6PD-deficient individuals is warranted. Finally, since GSH levels are lower in G6PD deficiency, it would be interesting to examine the effects of antioxidant or cysteine donor supplements on redox status after exercise in these individuals.

Exercise and Redox Status Responses Following Alpha-Lipoic Acid Supplementation in G6PD Deficient Individuals

G6PD deficiency renders cells more susceptible to oxidative insults, while antioxidant dietary supplementation could restore redox balance and ameliorate exercise-induced oxidative stress. To examine the effects of alpha-lipoic acid (ALA) supplementation on redox status indices in G6PD deficient individuals, eight male adults with G6PD deficiency (D) participated in this randomized double-blind placebo-controlled crossover trial. Participants were randomly assigned to receive ALA (600 mg/day) or placebo for 4 weeks separated by a 4-week washout period. Before and at the end of each treatment period, participants exercised following an exhaustive treadmill exercise protocol. Blood samples were obtained before (at rest), immediately after and 1h after exercise for later analysis of total antioxidant capacity (TAC), uric acid, bilirubin, thiobarbituric acid reactive substances (TBARS) and protein carbonyls (PC). ALA resulted in significantly increased resting TAC and bilirubin concentrations. Moreover, TAC increased immediately and 1h after exercise following both treatment periods, whereas bilirubin increased immediately after and 1h after exercise following only ALA. No significant change in uric acid, TBARS or PC was observed at any time point. ALA supplementation for 4 weeks may enhance antioxidant status in G6PD individuals; however, it does not affect redox responses to acute exercise until exhaustion or exercise performance.

Glucose-free/high-protein diet improves hepatomegaly and exercise intolerance in glycogen storage disease type III mice

Glycogen disease type III (GSDIII), a rare incurable autosomal recessive disorder due to glycogen debranching enzyme deficiency, presents with liver, heart and skeletal muscle impairment, hepatomegaly and ketotic hypoglycemia. Muscle weakness usually worsens to fixed myopathy and cardiac involvement may present in about half of the patients during disease. Management relies on careful follow-up of symptoms and diet. No common agreement was reached on sugar restriction and treatment in adulthood.

We administered two dietary regimens differing in their protein and carbohydrate content, high-protein (HPD) and high-protein/glucose-free (GFD), to our mouse model of GSDIII, starting at one month of age. Mice were monitored, either by histological, biochemical and molecular analysis and motor functional tests, until 10 months of age.

GFD ameliorated muscle performance up to 10 months of age, while HPD showed little improvement only in young mice. In GFD mice, a decreased muscle glycogen content and fiber vacuolization was observed, even in aged animals indicating a protective role of proteins against skeletal muscle degeneration, at least in some districts. Hepatomegaly was reduced by about 20%. Moreover, the long-term administration of GFD did not worsen serum parameters even after eight months of high-protein diet. A decreased phosphofructokinase and pyruvate kinase activities and an increased expression of Krebs cycle and gluconeogenesis genes were seen in the liver of GFD fed mice.

Our data show that the concurrent use of proteins and a strictly controlled glucose supply could reduce muscle wasting, and indicate a better metabolic control in mice with a glucose-free/high-protein diet.

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GSDIII is a rare incurable disease due to lacking of glycogen debrancher enzyme.

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Essential features are liver, heart and skeletal muscle impairment.

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Two diets differing in protein and sugar amount were tested in Agl-mouse model.

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Glucose-free/high-protein diet decreased glycogen storage and hepatomegaly.

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Improved muscle performance and better metabolic compensation were achieved.

New Diagnosis of G6PD Deficiency Presenting as Severe Rhabdomyolysis

A 24-year-old African-American man presented with malaise and low back pain and was found to have acute severe rhabdomyolysis followed by acute hemolysis. Glucose-6-phosphate dehydrogenase (G6PD) deficiency was suspected by the presence of blister cells on peripheral smear and was confirmed by a low enzyme activity assay. Our patient reported playing football, along with upper respiratory infection symptoms, prior to presentation. Extensive infectious and toxicology workup was negative; however, several inflammatory proteins were markedly elevated. We hypothesized the large inflammatory burden led to an increased reactive oxygen radical burden that overwhelmed muscle and erythrocyte reducing power. Severe rhabdomyolysis in G6PD deficiency is not a common presentation because skeletal muscles are more resistant to oxidative damage compared to red blood cells. Our case adds to the few existing reports of myolysis in the setting of G6PD deficiency.

Acute haemolytic anaemia and myolysis due to G6PD deficiency

A 2-year-old African-American male patient with sickle cell trait developed cough, red coloured urine, pallor and fatigue. The patient was hospitalised. Diagnostic workup showed that he was glucose 6 phosphate dehydrogenase (G6PD) deficient in erythrocytes. He also had chest X-ray findings of pneumonia. His urine examination showed the presence of haemoglobin and myoglobin. On repeated questioning it was found that he had a moth ball in his mouth a few days prior to this medical episode. This case illustrates a rarely described complication of myolysis in G6PD deficient persons on exposure to a strong oxidant. A review of the literature showed that most people with G6PD deficiency tolerate exercise well without untoward effect in muscles. However, assay of myoglobin in urine has not been routinely performed in these patients during acute haemolytic episode, and thus it is uncertain how frequent myoglobulinaemia occurs in a similar stress situation.

Acute anterior compartment syndrome associated with psychogenic polydipsia

OBJECTIVE

The aim of this paper is to describe the association of psychogenic polydipsia with anterior compartment syndrome.

METHOD

Case report.

RESULTS

A 31-year-old man with glucose-6-phosphate-dehydrogenase (G6PD) deficiency had a history of paranoid schizophrenia from age 16 complicated by the use of drugs. Four years after the initial diagnosis of schizophrenia, he developed psychogenic polydipsia. This was complicated by episodic severe acute hyponatraemia with seizures and, on one occasion, by generalized rhabdomyolysis. One episode of severe acute hyponatraemia with delirium led to anterior compartment syndrome in both legs. Delayed diagnosis and treatment led to extensive myonecrosis and permanent bilateral foot drop. For 6 years his polydipsia remained partially controlled in a locked psychiatric ward with limited leave, until his sudden death related to severe water intoxication.

CONCLUSIONS

Anterior compartment syndrome is a rare event associated with psychogenic polydipsia. Psychiatrists, physicians and surgeons should be aware of the seriousness of anterior compartment syndrome and its potential to increase morbidity in patients with psychogenic polydipsia.

Exercise-Induced Oxidative Stress in G6PD-Deficient Individuals

PURPOSE

This study was designed to investigate whether individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency can exercise without greater perturbations in their redox status compared with non-G6PD-deficient individuals.

METHODS

Nine males with established G6PD deficiency and nine males with normal G6PD activity performed two exhaustive treadmill exercise protocols of different duration (the shorter one lasting 12 min and the longer one 50 min). Several hematological parameters, reduced glutathione (GSH), oxidized glutathione (GSSG), thiobarbituric acid reactive substances (TBARS), protein carbonyls, catalase, and total antioxidant capacity (TAC) were measured in the blood before and after each exercise bout.

RESULTS

Both GSH and GSSG were significantly higher in the control group compared with the G6PD-deficient group at baseline (0.404 +/- 0.101 vs 0.195 +/- 0.049 mmol.L(-1) for GSH and 0.047 +/- 0.012 vs 0.012 +/- 0.006 mmol.L(-1) for GSSG; P < 0.05); as a result, their ratio was not significantly different between the two groups (P > 0.05). All other oxidative stress indices were not different between groups at rest (P > 0.05). Exercise of both durations affected significantly (P < 0.05) and similarly the levels of all oxidative stress indices either in the G6PD-deficient group or in the control group. Only the long exercise affected GSH status significantly (P < 0.05), whereas both short and long exercise increased the levels of TBARS, protein carbonyls, catalase activity, and TAC to a similar extent (P < 0.05).

CONCLUSION

G6PD-deficient individuals are able to exercise until exhaustion without higher oxidative stress compared with non-G6PD-deficient individuals. Exercise duration is an important determinant of the magnitude of exercise-induced changes for GSH, GSSG, and GSH/GSSG, but not for TBARS, protein carbonyls, catalase activity, or TAC.

Myoglobinuria

Myoglobinuria refers to an abnormal pathologic state in which an excessive amount of myoglobin is found in the urine, imparting a cola-like hue, usually in association with myonecrosis and a clinical picture of weakness, myalgias, and edema. Myoglobinuria is produced by multiple causes: any condition that accelerates the use or interferes with the availability of oxygen or energy substrates to muscle cells can result in myoglobinuria, as can events that produce direct muscle injury, either mechanical or chemical. Acute renal failure is the most serious complication, which can be prevented by prompt, aggressive treatment. In patients surviving acute attacks, recovery of muscle and renal function is usually complete.

Metabolic causes of recurrent rhabdomyolysis

OBJECTIVES

The aim of the study was to evaluate the biochemical causes of recurrent rhabdomyolysis in Finland.

MATERIAL AND METHODS

We examined 22 patients with recurrent rhabdomyolysis, and 26 patients with one episode of rhabdomyolysis or other symptoms compatible with metabolic myopathy. Muscle histopathology and activities of phosphorylase (PHRL) (total and active), phosphofructokinase (PFK), carnitine palmitoyltransferase (CPT) and myoadenylate deaminase (MAD) were studied. The limit of enzyme deficiency was defined as enzyme activity less than 5% of the mean of the control subjects.

RESULTS

We found 4 patients with muscle PHRL deficiency, 1 patient with PFK deficiency and 1 patient with evidence of phosphorylase kinase deficiency. One patient had Becker's muscle dystrophy, 2 patients had unspecified dystrophies, 1 patient had Miyoshi myopathy, and 1 patient had a form of mitochondrial encephalomyopathy (MELAS).

CONCLUSION

Enzyme defects were found in 23% of the patients with recurrent rhabdomyolysis. Other muscle diseases, muscular dystrophies or myopathies, were detected in 18% of these patients, emphasizing the value of clinical and histopathological examination of patients with previous rhabdomyolysis.

Metabolic myopathies

Disorders of glycogen, lipid or mitochondrial metabolism may cause two main clinical syndromes, namely (1) progressive weakness (eg, acid maltase, debrancher enzyme, and brancher enzyme deficiencies among the glycogenoses; long- and very-long-chain acyl-CoA dehydrogenase (LCAD, VLCAD), and trifunctional enzyme deficiencies among the fatty acid oxidation (FAO) defects; and mitochondrial enzyme deficiencies) or (2) acute, recurrent, reversible muscle dysfunction with exercise intolerance and acute muscle breakdown or myoglobinuria (with or without cramps) (eg, phosphorylase (PPL), phosphorylase b kinase (PBK), phosphofructokinase (PFK), phosphoglycerate kinase (PGK), phosphoglycerate mutase (PGAM), and lactate dehydrogenase (LDH) among the glycogenoses and carnitine palmitoyltransferase II (CPT II) deficiency among the disorders of FAO or (3) both (eg, PPL, PBK, PFK among the glycogenoses; LCAD, VLCAD, short-chain L-3-hydroxyacyl-CoA dehydrogenase (SCHAD), and trifunctional enzyme deficiencies among the FAO defects; and multiple mitochondrial DNA (mtDNA) deletions). Myoadenylate deaminase deficiency, a purine nucleotide cycle defect, is somewhat controversial and is characterized by exercise-related cramps leading rarely to myoglobinuria.

Muscle expression of glucose-6-phosphate dehydrogenase deficiency in different variants

Muscle expression of G6PD deficiency has been investigated in Mediterranean, Seattle-like and A-variants. G6PD activity was detected in samples obtained from biopsies on the quadriceps muscle of seven males and one female. The type of genetic variant was determined by molecular analysis of DNA, extracted from blood samples. All variants showed the enzyme defect in muscle. A statistically significant relationship was found in the activity of G6PD between erythrocytes and muscle of the male subjects (r = 0.968; p = 0.00008). The equation for the best fit line was: Y = 0.390X + 0.198. The results suggest that, for a given variant, the extent of the enzyme defect in muscle may be determined, using this equation, from the G6PD activity of erythrocytes.

Immunocytochemistry of muscle cytoskeletal proteins in acid maltase deficiency

Immunocytochemistry of dystrophin, spectrin, vinculin (sarcolemma-specific proteins), and desmin (an intermediate filament protein) were investigated in 5 patients with acid maltase deficiency (AMD). One patient had infant onset, 2 had childhood onset, and 2 had adult onset. All had a vacuolar myopathy with autophagic vacuoles containing glycogen and cytoplasmic degradation products. Dystrophin, spectrin, and vinculin were localized at the sarcolemma as in normal muscle fibers. Within the cytoplasm of many fibers, immunoreactivity for the three proteins was seen as single or multiple spots or as circular structures, which most likely corresponded to the limiting membrane of vacuoles. Desmin was overexpressed at the periphery of some vacuoles. It is plausible that, before exocytosis occurs, sarcolemma-specific proteins appear within the vacuole membrane. Vacuole immunolabeling frequently occurred in the patients with childhood and adult onset AMD, but very rarely occurred in the case with infant onset. We hypothesize that a reduced exocytosis rate might explain the infrequent vacuole immunolabeling and the early onset of the infant form of the disease.

Muscle phosphoglycerate mutase (PGAM) deficiency in the first Caucasian patient: biochemistry, muscle culture and 31P-MR spectroscopy

Muscle phosphoglycerate mutase (PGAM) deficiency has been so far identified in only six patients, five of these being African Americans. We report the results of clinical, morphological, biochemical, muscle culture and 31P-MR spectroscopy studies in the first Caucasian patient with muscle PGAM deficiency. A 23-year-old man had a 10-year history of cramps after physical exertion with one episode of pigmenturia. Neurological examination and EMG study were normal. ECG and echocardiography revealed hypertrophy of the interventricular septum and slight dilation of the left chambers of the heart. Muscle biopsy revealed increased glycogen content and some accumulation of mitochondria. Muscle PGAM activity was markedly decreased (6.5% and 9.7% of control value in two different biopsies). Citrate synthase and other mitochondrial respiratory chain enzyme activities were much higher than normal. In contrast to the marked decrease of PGAM activity observed in muscle biopsy, total enzyme activity in the patient's aneural muscle culture was normal, being represented exclusively by BB isoenzyme. The deficiency of PGAM-MM isoenzyme was reproduced in the patient's innervated muscle culture. Muscle 31P-MR spectroscopy showed accumulation of phosphomonoesters only on fast "glycolytic" exercise. On "aerobic" exercise, Vmax, calculated from the work-energy cost transfer function, showed an increase consistent with the morphological and biochemical evidence of mitochondrial proliferation. This might represent a sort of compensatory aerobic effort in an attempt to restore muscle power.

Muscle glucose-6-phosphate dehydrogenase deficiency: restoration of enzymatic activity in hybrid myotubes

A high level of glucose-6-phosphate dehydrogenase (G6PD) activity was observed in myoblasts and myotubes from normal human and mouse cell cultures. However, only a residual amount of activity was observed in myoblasts and myotubes obtained from G6PD-deficient patients (G6PD Mediterranean). Hybrids were formed by the fusion of normal (from human and mouse) and G6PD-deficient myoblasts (from the patients). These hybrids contained a high level of G6PD activity. Hoechst staining permitted to confirm that the enzymatic activity was not restrained to a domain near the competent nuclei. These results suggest that myoblast transplantation could be used to restore normal enzymatic activity in metabolic myopathies.

Stable hybrid myotubes: a new model for studying re-expression of enzymatic activities in vitro

Heterokaryons represent a stable and reproducible model system for the study of biochemical and molecular aspects responsible for muscle gene activation. Previous experiments have used this fusion system to demonstrate human gene activation in hybrids formed between human and non-human cells. The aim of this research was to apply this experimental model to the correction of a cytoplasmic activity, namely glucose-6-phosphate dehydrogenase (G6PD), in vitro, in hybrid myotubes formed between G6PD-negative and positive myoblasts. Different identification methods were used (Hoechst stain and Fluorescent Latex Microspheres, FLMs) to identify hybrid myotubes formed. We demonstrated the restoration of G6PD activity in all hybrid myotubes formed; we then tried to elucidate the mechanisms underlying the restoration of this specific activity and apply the results obtained to the understanding of more complex mechanisms involved in muscle gene activation.

Hereditary human myopathies in muscle culture

In this article I illustrated the use of regenerating human muscle cultures for studying the hereditary human myopathies. Although some of the data are still controversial, they do point up the great potential of this "in vitro system". For hereditary myopathies due to developmentally regulated proteins that are expressed only at a more advanced stage of muscle differentiation, the use of highly differentiated nerve-muscle cocultures might contribute significantly to a better understanding of their developmental pathogenesis. More advanced techniques (permanent human muscle cell lines, heterokaryons, myoblast transfer, gene transfer, myogenic conversion of human non-muscle cells, cybrid clones) may provide a great deal of information at molecular level and may also have practical applications in the diagnosis or even in the treatment of hereditary human myopathies.