Effects of acute nutritional ketosis during exercise in adults with glycogen storage disease type IIIa are phenotype-specific: An investigator-initiated, randomized, crossover study

Glycogen storage disease type IIIa (GSDIIIa) is an inborn error of carbohydrate metabolism caused by a debranching enzyme deficiency. A subgroup of GSDIIIa patients develops severe myopathy. The purpose of this study was to investigate whether acute nutritional ketosis (ANK) in response to ketone-ester (KE) ingestion is effective to deliver oxidative substrate to exercising muscle in GSDIIIa patients. This was an investigator-initiated, researcher-blinded, randomized, crossover study in six adult GSDIIIa patients. Prior to exercise subjects ingested a carbohydrate drink (~66 g, CHO) or a ketone-ester (395 mg/kg, KE) + carbohydrate drink (30 g, KE + CHO). Subjects performed 15-minute cycling exercise on an upright ergometer followed by 10-minute supine cycling in a magnetic resonance (MR) scanner at two submaximal workloads (30% and 60% of individual maximum, respectively). Blood metabolites, indirect calorimetry data, and in vivo ³¹ P-MR spectra from quadriceps muscle were collected during exercise. KE + CHO induced ANK in all six subjects with median peak βHB concentration of 2.6 mmol/L (range: 1.6-3.1). Subjects remained normoglycemic in both study arms, but delta glucose concentration was 2-fold lower in the KE + CHO arm. The respiratory exchange ratio did not increase in the KE + CHO arm when workload was doubled in subjects with overt myopathy. In vivo ³¹ P MR spectra showed a favorable change in quadriceps energetic state during exercise in the KE + CHO arm compared to CHO in subjects with overt myopathy. Effects of ANK during exercise are phenotype-specific in adult GSDIIIa patients. ANK presents a promising therapy in GSDIIIa patients with a severe myopathic phenotype. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT03011203.

Dietary lipids in glycogen storage disease type III: A systematic literature study, case studies, and future recommendations

A potential role of dietary lipids in the management of hepatic glycogen storage diseases (GSDs) has been proposed, but no consensus on management guidelines exists. The aim of this study was to describe current experiences with dietary lipid manipulations in hepatic GSD patients. An international study was set up to identify published and unpublished cases describing hepatic GSD patients with a dietary lipid manipulation. A literature search was performed according to the Cochrane Collaboration methodology through PubMed and EMBASE (up to December 2018). All delegates who attended the dietetics session at the IGSD2017, Groningen were invited to share unpublished cases. Due to multiple biases, only data on GSDIII were presented. A total of 28 cases with GSDIII and a dietary lipid manipulation were identified. Main indications were cardiomyopathy and/or myopathy. A high fat diet was the most common dietary lipid manipulation. A decline in creatine kinase concentrations (n = 19, P < .001) and a decrease in cardiac hypertrophy in paediatric GSDIIIa patients (n = 7, P < .01) were observed after the introduction with a high fat diet. This study presents an international cohort of GSDIII patients with different dietary lipid manipulations. High fat diet may be beneficial in paediatric GSDIIIa patients with cardiac hypertrophy, but careful long-term monitoring for potential complications is warranted, such as growth restriction, liver inflammation, and hepatocellular carcinoma development.

Hepatic glycogen storage disorders: what have we learned in recent years?

PURPOSE OF REVIEW

Glycogen storage disorders (GSDs) are inborn errors of metabolism with abnormal storage or utilization of glycogen. The present review focuses on recent advances in hepatic GSD types I, III and VI/IX, with emphasis on clinical aspects and treatment.

RECENT FINDINGS

Evidence accumulates that poor metabolic control is a risk factor for the development of long-term complications, such as liver adenomas, low bone density/osteoporosis, and kidney disease in GSD I. However, mechanisms leading to these complications remain poorly understood and are being investigated. Molecular causes underlying neutropenia and neutrophil dysfunction in GSD I have been elucidated. Case series provide new insights into the natural course and outcome of GSD types VI and IX. For GSD III, a high protein/fat diet has been reported to improve (cardio)myopathy, but the beneficial effect of this dietary concept on muscle and liver disease manifestations needs to be further established in prospective studies.

SUMMARY

Although further knowledge has been gained regarding pathophysiology, disease course, treatment, and complications of hepatic GSDs, more controlled prospective studies are needed to assess effects of different dietary and medical treatment options on long-term outcome and quality of life.

Dietary management in glycogen storage disease type III: what is the evidence?

In childhood, GSD type III causes relatively severe fasting intolerance, classically associated with ketotic hypoglycaemia. During follow up, history of (documented) hypoglycaemia, clinical parameters (growth, liver size, motor development, neuromuscular parameters), laboratory parameters (glucose, lactate, ALAT, cholesterol, triglycerides, creatine kinase and ketones) and cardiac parameters all need to be integrated in order to titrate dietary management, for which age-dependent requirements need to be taken into account. Evidence from case studies and small cohort studies in both children and adults with GSD III demonstrate that prevention of hypoglycaemia and maintenance of euglycemia is not sufficient to prevent complications. Moreover, over-treatment with carbohydrates may even be harmful. The ageing cohort of GSD III patients, including the non-traditional clinical presentations in adulthood, raises ‬‬‬new questions.

The effect of tailoring of cornstarch intake on stature in children with glycogen storage disease type III

AIM

To determine the individual fasting tolerance for patients with glycogen storage disease type III (GSD III) and to assess their linear growth velocity after tailoring of dose intervals of oral uncooked cornstarch.

PATIENTS AND METHODS

A prospective cohort study included 32 patients with GSD III aged 6 months-11.5 years (median: 3.3 years). The fasting tolerance of each patient was determined as the time interval between starch administration until the drop in blood glucose level was below 60 mg/dL.

RESULTS

Some 27 patients (84.4%) developed hypoglycemia. The intervals between oral cornstarch administration were tailored for each child according to his/her individual fasting tolerance. After a 6-month follow up there was a significant reduction in seizure attacks (p<0.01) and liver size (p<0.01), but there was no statistically significant difference in liver transaminase and serum lactate levels. There was a significant improvement in height (p<0.01) and linear growth velocity (p<0.05) of these patients after at least a 12-month follow up.

CONCLUSION

Adjusting the intervals between the cornstarch doses for each patient with GSD III, according to individual fasting tolerance test was very beneficial and resulted in improvement of the linear growth velocity and reduction in the frequency of hypoglycemic seizures as well as the size of the liver. Individual scheduling of cornstarch doses prevents complications in those who develop hypoglycemia at short intervals; it also allows some relaxation in schedule for those who can tolerate longer fasting hours to improve their appetite and prolong their uninterrupted sleep hours.

Reversal of glycogen storage disease type IIIa-related cardiomyopathy with modification of diet

Glycogen storage disease type III (GSD III) is caused by a deficiency in debranching enzyme, which leads to an accumulation of abnormal glycogen called limit dextrin in affected tissues. Muscle and liver involvement is present in GSD type IIIa, while the defect is limited to the liver only in GSD type IIIb. Besides skeletal muscle involvement, a cardiomyopathy resembling idiopathic hypertrophic cardiomyopathy is seen. Management consists of maintaining normoglycaemia by supplementation with cornstarch therapy and/or protein. While studies are lacking regarding the best treatment for skeletal muscle disease, a high-protein diet was previously reported to be beneficial. No cases of improvement in cardiomyopathy have been reported. Our patient presented in infancy with hypoglycaemia and hepatomegaly. His prescribed management consisted of cornstarch supplementation and a high-protein diet providing 20% of his total energy needs. At 16 years of age, he developed a severe cardiomyopathy with a left ventricular mass index of 209 g/m(2). The cardiomyopathy remained stable on a protein intake of 20-25% of total energy. At age 22 years, the diet was changed to increase his protein intake to 30% of total energy and minimize his cornstarch therapy to only what was required to maintain normoglycaemia. Dramatic improvement in the cardiomyopathy occurred. Over one year, his left ventricular mass index decreased from 159.7 g/m(2) to 78 g/m(2) (normal 50-86 g/m(2)) and the creatine kinase levels decreased from 455 U/L to 282 U/L. Avoidance of overtreatment with carbohydrate and a high-protein diet can reverse and may prevent cardiomyopathy.

Severe hypoglycaemia in a patient with glycogen storage disease type III induced by infectious mononucleosis

A 10-month-old girl with glycogen storage disease type III developed recurrent severe hypoglycaemia induced by infectious mononucleosis. Severe metabolic damage probably reflected a rapid breakdown of liver cells induced by the viral infection.

Liver transplantation for glycogen storage disease types I, III, and IV

Glycogen storage disease (GSD) types I, III, and IV can be associated with severe liver disease. The possible development of hepatocellular carcinoma and/or hepatic failure make these GSDs potential candidates for liver transplantation. Early diagnosis and initiation of effective dietary therapy have dramatically improved the outcome of GSD type I by reducing the incidence of liver adenoma and renal insufficiency. Nine type I and 3 type III patients have received liver transplants because of poor metabolic control, multiple liver adenomas, or progressive liver failure. Metabolic abnormalities were corrected in all GSD type I and type III patients, while catch-up growth was reported only in two patients. Whether liver transplantation results in reversal and/or prevention of renal disease remains unclear. Neutropenia persisted in both GSDIb patients post liver transplantation necessitating continuous granulocyte colony stimulating factor treatment. Thirteen GSD type IV patients were liver transplanted because of progressive liver cirrhosis and failure. All but one patient have not had neuromuscular or cardiac complications during follow-up periods for as long as 13 years. Four have died within a week and 5 years after transplantation. Caution should be taken in selecting GSD type IV candidates for liver transplantation because of the variable phenotype, which may include life-limiting extrahepatic manifestations. It remains to be evaluated, whether a genotype-phenotype correlation exists for GSD type IV, which may aid in the decision making.

CONCLUSION

Liver transplantation should be considered for patients with glycogen storage disease who have developed liver malignancy or hepatic failure, and for type IV patients with the classical and progressive hepatic form.

[Corn starch in the treatment of patients with glycogenosis type I and III]

RATIONALE

Administering raw corn starch can maintain normoglycemia for long periods after being ingested, thus facilitating control in patients with type I and III glycogenosis.

METHODS

The metabolic effects and the effects on the nutritional status of a treatment with fractionated administrations of raw starch are assessed in two patients with type I glycogenosis (ages 18 and 12 years) and one patient with type III glycogenosis (aged 13 years). In the first two cases the response was previously studied after administering a load of raw corn starch in a water suspension, in an amount similar to the estimated rate of endogenous glucose production during the fasting period (5 mg/kg/minute).

RESULTS

The results of the overload of starch showed a normoglycemia and an absence of lactoacidosis between 4 and 6 hours after its ingestion. The three patients were given two doses of raw corn starch (2 g/kg/dose) at 1.00 and 5.00 hours during the night. After one year of treatment, all patients showed glycemia levels at 9.00 AM that were greater than 90 mg/dl and lactic acid levels that were lower than 2.4 mmol/l. Moreover, in two of the cases there was an increase in the growth rate. In all cases the amount of the hepatomegaly decreased as did the size of the hepatic adenomas that were present in two of the cases.

CONCLUSIONS

In patients with type I and III glycogenosis, raw corn starch can balance the results of the nightly gastric glucose infusion, both with regard to the metabolic control and with regard to the growth.

Nutrition therapy for hepatic glycogen storage diseases

Hepatic glycogen storage diseases (GSD) are a group of rare genetic disorders in which glycogen cannot be metabolized to glucose in the liver because of one of a number of possible enzyme deficiencies along the glycogenolytic pathway. Patients with GSD are usually diagnosed in infancy or early childhood with hypoglycemia, hepatomegaly, poor physical growth, and a deranged biochemical profile. Dietary therapies have been devised to use the available alternative metabolic pathways to compensate for disturbed glycogenolysis in GSD I (glucose-6-phosphatase deficiency), GSD III (debrancher enzyme deficiency), GSD VI (phosphorylase deficiency, which is less common), GSD IX (phosphorylase kinase deficiency), and GSD IV (brancher enzyme deficiency). In GSD I, glucose-6-phosphate cannot be dephosphorylated to free glucose. Managing this condition entails overnight continuous gastric high-carbohydrate feedings; frequent daytime feedings with energy distributed as 65% carbohydrate, 10% to 15% protein, and 25% fat; and supplements of uncooked cornstarch. In GSD III, though glycogenolysis is impeded, gluconeogenesis is enhanced to help maintain endogenous glucose production. In contrast to treatment for GSD I, advocated treatment for GSD III comprises frequent high-protein feedings during the day and a high-protein snack at night; energy is distributed as 45% carbohydrate, 25% protein, and 30% fat. Patients with GSD IV, VI, and IX have benefited from high-protein diets similar to that recommended for patients with GSD III.

Diet therapy in severe clinical expression of debrancher deficiency

An eleven year old boy was referred because of sudden loss of consciousness, muscular weakness, poor general health, severe hypoglycemia with seizures and hepatomegaly. Response to oral glucose and galactose increased blood lactic acid and glucose at different times. Fasting values of blood lactic was normal, but glucose was found at 33 mg/dl. Similar test made up two hours after feeding revealed hyperlactatemia (35-50 mg/dL) and hyperglycemia (129 mg/dL). Glucagon did not result in a rise of glucose at fasting or feeding. Hepatic glycogen content was found 15 gm/100 mg of tissue. The enzyme activities revealed a deficiency of the liver debranching enzyme while leukocytes had normal enzyme activity. Hepatic biopsy showed liver fibrosis. The present case had the clinical characteristics of severe form of glycogen storage disease. A low carbohydrate and high protein diet was indicated in order to increase the gluconeogenic precursors. Although debranching enzyme deficiency is almost always benign a high carbohydrate diet induced a more severe expression of the disease.

Glycogen storage disease type I and III and pyruvate carboxylase deficiency: results of long-term treatment with uncooked cornstarch

Three patients with glycogen storage disease type I (GSD-I), three with glycogen storage disease type III (GSD-III) and one with pyruvate carboxylase deficiency (PCD) could be successfully switched over from continuous nocturnal gastric drip feeding (GDF) to nocturnal feeding with uncooked cornstarch in yoghurt or "quark" (CSF) at the age of 4-20 years. The new kind of therapy is much more convenient for the patients. When followed up to 30 months, patients on CSF showed the same clinical and laboratory findings as during the last two years with GDF. CSF was not introduced to three patients with GSD-I. Two of them refused the permanent starch-yoghurt meals. In the third patient the morning blood glucose concentrations were too variable.

Glycogen storage disease: recommendations for treatment

A workshop was held on "Aspects of treatment of patients with glycogen storage disease" within the framework of the Concerted Action "Inborn errors of metabolism" of the European Communities. Consensus was reached on the main issues of treatment of patients with deficiency of glucose-6-phosphatase, glucose-6-phosphate translocase, debranching enzyme, liver phosphorylase and phosphorylase-b-kinase. The resulting recommendations are reported.

Cornstarch therapy in a patient with type III glycogen storage disease

A child with type III glycogen storage disease is described. The patient presented with growth failure and hepatic dysfunction, and no clinical or biochemical evidence of myopathy. Institution of high protein nocturnal intragastric feedings was associated with improved growth and less hepatic dysfunction. Compliance with tube feedings was sporadic necessitating another approach to the patient's management. The use of oral cornstarch supplements enabled the child to maintain normoglycemia and was associated with clinical and biochemical improvement. Our experience with this child suggests cornstarch therapy may be useful in those patients with type III glycogen storage disease who suffer primarily from hepatic dysfunction and growth failure.

Diet and growth of children with glycogen storage disease Types I and III

Patients with glycogen storage disease (GSD) Types I and III were placed on a dietary treatment plan of frequent daytime feedings and continuous drip nocturnal enteral feedings of defined nutrient composition. Specific anthropometric measurements were collected to document and evaluate growth. There were a significant increase in arm muscle area and a relative decrease in triceps skinfold thickness not previously documented in the literature. Study results confirmed previous reports of accelerated growth and improvement of biochemical abnormalities. The dietitian's role in nutrition assessment and dietary management of GSD patients is emphasized.

Reversal of debrancher deficiency myopathy by the use of high-protein nutrition

A child with debrancher deficiency presented with myopathy, recurrent hypoglycemia, and growth failure. Evidence for enhanced gluconeogenesis was demonstrated by low postabsorptive gluconeogenic plasma amino acids, a marked fall in alanine during fasting, and a substantial rise in plasma glucose following protein ingestion. The patient was treated with high-protein nocturnal intragastric therapy, which resulted in marked improvement in exercise tolerance, muscle strength and mass, electromyographic findings, and growth.