Glycogen Storage Research Articles

Unraveling the genetic tapestry of pediatric sarcomeric cardiomyopathies and masquerading phenocopies in Jordan

Pediatric cardiomyopathies are mostly attributed to variants in sarcomere-related genes. Unfortunately, the genetic architecture of pediatric cardiomyopathies has never been previously studied in Jordan. We sought to uncover the genetic landscape of 14 patients from nine families with several subtypes of pediatric cardiomyopathies in Jordan using Exome sequencing (ES). Our investigation identified pathogenic and likely pathogenic variants in seven out of nine families (77.8%), clustering in sarcomere-related genes. Surprisingly, phenocopies of sarcomere-related hypertrophic cardiomyopathies were evident in probands with glycogen storage disorder and mitochondrial-related disease. Our study underscored the significance of streamlining ES or expanding cardiomyopathy-related gene panels to identify plausible phenocopies of sarcomere-related cardiomyopathies. Our findings also pointed out the need for genetic testing in patients with cardiomyopathy and their at-risk family members. This can potentially lead to better management strategies, enabling early interventions, and ultimately enhancing their prognosis. Finally, our findings provide an initial contribution to the currently absent knowledge about the molecular underpinnings of cardiomyopathies in Jordan.

Hypoglycemic Action of Glycocar on Insulin and Glucose Metabolism In Vivo

Background: Diabetes mellitus, particularly type 2, presents a growing global health challenge, with an estimated 700 million people expected to be affected by 2045. The disease is characterized by insulin resistance and impaired insulin secretion, necessitating effective treatments. This study aimed to explore the hypoglycemic mechanisms of Glykokar, a herbal formulation, in rats with alloxan-induced diabetes. The objective of this study was to investigate the hypoglycemic mechanisms of Glykokar, a herbal formulation. Methods: Eighteen rats with alloxan-induced diabetes were divided into groups receiving Glykokar at doses of 50 mg/kg or 100 mg/kg, and a control group receiving saline. The study measured the effects of Glykokar on C-peptide levels, glycogen content in liver and muscle, and the activity of hexokinase and phosphorylase enzymes over 7 and 14 days. Results: Results demonstrated that Glykokar significantly increased C-peptide levels, with the 100 mg/kg dose showing the greatest effect, enhancing C-peptide by 87.5% on day 14 compared to controls. Glycogen content in liver and muscle tissues was also elevated, particularly at the 100 mg/kg dose, which increased liver glycogen by 86% and muscle glycogen by 50%. Enzyme activity studies revealed that Glykokar reduced phosphorylase activity in diabetic muscle tissue and significantly boosted hexokinase and glucokinase activities, with the highest effects seen at the 100 mg/kg dose. Conclusion: The findings suggest that Glykokar’s hypoglycemic action is mediated through enhanced glucose metabolism in tissues, driven by increased enzymatic activity and glycogen storage. This study provides evidence for the potential of Glykokar as a therapeutic agent in managing hyperglycemia by improving glucose utilization and insulin secretion.

Meldonium Supplementation in Professional Athletes: Career Destroyer or Lifesaver?

Meldonium is a substance with known anti-anginal effects demonstrated by numerous studies and human clinical trials; however, it does not possess marketing authorization within the European Union, only in ex-Soviet republics. Since 2016, meldonium has been included by the World Anti-doping Agency (WADA) on the S4 list of metabolic modulators. In performance athletes, meldonium is now considered a doping agent due to its capacity to decrease lactate production during and after exercise, its capability to enhance the storage and utilization of glycogen, and its protective action against oxidative stress. Together, these attributes can significantly improve aerobic endurance, cardiac function, and capacityas well as shorten recovery times (allowing higher intensity training), thereby enhancing performance. The purpose of this review is to highlight the most important mechanisms underlying the protective effect of meldonium against mitochondrial dysfunction (MD), which is responsible for oxidative stress, inflammation, and the cardiac changes known as "athletic heart syndrome."Meldonium acts as an inhibitor of γ-butyrobetaine hydroxylase (BBOX), preventing the de novo synthesis of carnitine and its absorption at the intestinal level via the organic cation/carnitine transporter 2 (OCTN2) and directing the oxidation of fatty acids to the peroxisomes. The decrease in mitochondrial β-oxidation of fatty acids leads to a reduction in lipid peroxidation products that cause oxidative stress and prevent the formation of acyl/acetyl-carnitines involved in numerous pathological disorders. Given the recent findings of the potentially detrimental effects of prolonged high-intensity exercise on cardiovascular health and coronary atherosclerosis, there may be legitimate arguments for the justification of the use of substances likemeldonium as protective supplements for athletes.

A Functional Human Glycogen Debranching Enzyme Encoded by a Synthetic Gene: Its Implications for Glycogen Storage Disease Type III Management.

Glycogen Storage Disease type III (GSD III) is a metabolic disorder resulting from a deficiency of the Glycogen Debranching Enzyme (GDE), a large monomeric protein (approximately 170 kDa) with cytoplasmic localization and two distinct enzymatic activities: 4-α-glucantransferase and amylo-α-1,6-glucosidase. Mutations in the Agl gene, with consequent deficiency in GDE, lead to the accumulation of abnormal/toxic glycogen with shorter chains (phosphorylase limit dextrin, PLD) in skeletal and/or heart muscle and/or in the liver. Currently, there is no targeted therapy, and available treatments are symptomatic, relying on specific diets. Enzyme Replacement Therapy (ERT) might represent a potential therapeutic strategy for GSD III. Moreover, the single-gene nature of GSD III, the subcellular localization of GDE, and the type of affected tissues represent ideal conditions for exploring gene therapy approaches. Toward this direction, we designed a synthetic, codon-optimized cDNA encoding the human GDE. This gene yielded high amounts of soluble, enzymatically active protein in Escherichia coli. Moreover, when transfected in Human Embryonic Kidney cells (HEK-293), it successfully encoded a functional GDE. These results suggest that our gene or protein might complement the missing function in GSD III patients, opening the door to further exploration of therapeutic approaches for this disease.

Unraveling a history of overlap: A phenotypic comparison of RBCK1-related disease and glycogen storage disease type IV.

RBCK1-related disease is a rare, multisystemic disorder for which our current understanding of the natural history is limited. A number of individuals initially carried clinical diagnoses of glycogen storage disease IV (GSD IV), but were later found to harbor RBCK1 pathogenic variants, demonstrating challenges of correctly diagnosing RBCK1-related disease. This study carried out a phenotypic comparison between RBCK1-related disease and GSD IV to identify features that clinically differentiate these diagnoses. Literature review and retrospective chart review identified 25 individuals with RBCK1-related disease and 36 with the neuromuscular subtype of GSD IV. Clinical features were evaluated to assess for statistically significant differences between the conditions. At a system level, any cardiac, autoinflammation, immunodeficiency, growth, or dermatologic involvement were suggestive of RBCK1, whereas any respiratory involvement suggested GSD IV. Several features warrant further exploration as predictors of RBCK1, such as generalized weakness, heart transplant, and recurrent infections, among others. Distinguishing RBCK1-related disease will facilitate correct diagnoses and pave the way for accurately identifying affected individuals, as well as for developing management recommendations, treatment, and an enhanced understanding of the natural history. This knowledge may also inform which individuals thought to have GSD IV should undergo reevaluation for RBCK1.

Preserving Hepatic Glycogen Stores: Investigating the Therapeutic Influence of Vitamin E in Alcoholic Liver Injury-Induced Intracellular Carbohydrate Depletion

Preserving Hepatic Glycogen Stores: Investigating the Therapeutic Influence of Vitamin E in Alcoholic Liver Injury-Induced Intracellular Carbohydrate Depletion

Long term administration of thiamine disulfide improves FOXO1/PEPCK pathway in liver to reduce insulin resistance in type 1 diabetes rat model

ObjectiveThe main objective of this study was to find if thiamine disulfide (TD) lowers blood glucose level and improves insulin resistance (IR) in liver and muscle in rats with chronic type 1 diabetes (T1DM) using euglycemic-hyperinsulinemic clamp technique. MethodsA total of fifty male Wistar rats were assigned to five groups consisted of: non-diabetic control (NDC), diabetic control (DC), diabetic treated with thiamine disulfide (D-TD), diabetic treated with insulin (D-insulin), and diabetic treated with both TD and insulin (D-insulin+TD). Diabetes was induced by a 60 mg/kg dose of streptozotocin. Blood glucose levels, pyruvate tolerance test (PTT), intraperitoneal glucose tolerance test (IPGTT), levels of glycosylated hemoglobin (HbA1c), glucose infusion rate (GIR), liver and serum lipid profiles, liver glycogen stores, liver enzymes ([ALT], [AST]), and serum calcium and magnesium levels. were evaluated. Additionally, gene expression levels of phosphoenolpyruvate carboxykinase (Pepck), forkhead box O1 (Foxo1), and glucose transporter type 4 (Glut4) were assessed in liver and skeletal muscle tissues. ResultsBlood glucose level was reduced by TD treatment. In addition, TyG index, HOMA-IR, serum and liver lipid profiles, HbA1c levels, and expressions of Foxo1 and Pepck genes were decreased significantly (P<0.05) in all the treated groups. However, TD did not influence Glut4 gene expression, but GIR as a critical index of IR were 5.0±0.26, 0.29±0.002, 1.5±0.07, 0.9±0.1 and 1.3±0.1 mg.min−1Kg−1 in NDC, DC, D-TD, D-insulin and D-insulin+TD respectively. ConclusionsTD improved IR in the liver primarily by suppressing gluconeogenic pathways, implying the potential use of TD as a therapeutic agent in diabetes.

Metabolic recovery from submaximal exercise in hypoxia acclimated high altitude deer mice (Peromyscus maniculatus)

Animals living at high-altitude are faced with unremitting low oxygen availability. This can make it difficult to perform daily tasks that require increases in aerobic metabolism. An activity important for survival is aerobic locomotion, and the rapid recovery of muscle metabolism post exercise. Past work shows that hypoxia acclimated high-altitude mice (Peromyscus maniculatus) have a greater reliance on carbohydrates to power exercise than low altitude mice. However, it is unclear how quickly after aerobic exercise these mice can recovery and replenish muscle glycogen stores. The gastrocnemius muscle of high-altitude deer mice has a more aerobic phenotype and a greater capacity to oxidize lipids than low altitude deer mice. This suggests that high altitude mice may recover more rapidly from exercise than their lowland counterparts due to a greater capacity to support glycogen replenishment using intramuscular triglycerides (IMTG). To explore this possibility, we used low- and high-altitude native deer mice born and raised in common lab conditions and acclimated to chronic hypoxia. We determined changes in oxygen consumption following 15 min of aerobic exercise in 12% O2 and sampled skeletal muscles and liver at various time points during recovery to examine changes in key metabolites, including glycogen and IMTG. We found depletion in glycogen stores during exercise only in lowlanders, which returned to resting levels following 90 min of recovery. In contrast, IMTG did not change significantly with exercise or during recovery in either population. These data suggest that exercise recovery is influenced by altitude ancestry in deer mice.

Efficacy of Lactococcus lactis subsp. lactis LY-66 and Lactobacillus plantarum PL-02 in Enhancing Explosive Strength and Endurance: A Randomized, Double-Blinded Clinical Trial.

Probiotics are posited to enhance exercise performance by influencing muscle protein synthesis, augmenting glycogen storage, and reducing inflammation. This double-blind study randomized 88 participants to receive a six-week intervention with either a placebo, Lactococcus lactis subsp. lactis LY-66, Lactobacillus plantarum PL-02, or a combination of both strains, combined with a structured exercise training program. We assessed changes in maximal oxygen consumption (VO2max), exercise performance, and gut microbiota composition before and after the intervention. Further analyses were conducted to evaluate the impact of probiotics on exercise-induced muscle damage (EIMD), muscle integrity, and inflammatory markers in the blood, 24 and 48 h post-intervention. The results demonstrated that all probiotic groups exhibited significant enhancements in exercise performance and attenuation of muscle strength decline post-exercise exhaustion (p < 0.05). Notably, PL-02 intake significantly increased muscle mass, whereas LY-66 and the combination therapy significantly reduced body fat percentage (p < 0.05). Analysis of intestinal microbiota revealed an increase in beneficial bacteria, especially a significant rise in Akkermansia muciniphila following supplementation with PL-02 and LY-66 (p < 0.05). Overall, the combination of exercise training and supplementation with PL-02, LY-66, and their combination improved muscle strength, explosiveness, and endurance performance, and had beneficial effects on body composition and gastrointestinal health, as evidenced by data obtained from non-athlete participants.

Induced Pluripotent Stem Cells and CRISPR-Cas9 Innovations for Treating Alpha-1 Antitrypsin Deficiency and Glycogen Storage Diseases.

Human induced pluripotent stem cell (iPSC) and CRISPR-Cas9 gene-editing technologies have become powerful tools in disease modeling and treatment. By harnessing recent biotechnological advancements, this review aims to equip researchers and clinicians with a comprehensive and updated understanding of the evolving treatment landscape for metabolic and genetic disorders, highlighting how iPSCs provide a unique platform for detailed pathological modeling and pharmacological testing, driving forward precision medicine and drug discovery. Concurrently, CRISPR-Cas9 offers unprecedented precision in gene correction, presenting potential curative therapies that move beyond symptomatic treatment. Therefore, this review examines the transformative role of iPSC technology and CRISPR-Cas9 gene editing in addressing metabolic and genetic disorders such as alpha-1 antitrypsin deficiency (A1AD) and glycogen storage disease (GSD), which significantly impact liver and pulmonary health and pose substantial challenges in clinical management. In addition, this review discusses significant achievements alongside persistent challenges such as technical limitations, ethical concerns, and regulatory hurdles. Future directions, including innovations in gene-editing accuracy and therapeutic delivery systems, are emphasized for next-generation therapies that leverage the full potential of iPSC and CRISPR-Cas9 technologies.

Gut Dysbiosis Drives Inflammatory Bowel Disease Through the CCL4L2-VSIR Axis in Glycogen Storage Disease.

Patients with glycogen storage disease type Ib (GSD-Ib) frequently have inflammatory bowel disease (IBD). however, the underlying etiology remains unclear. Herein, this study finds that digestive symptoms are commonly observed in patients with GSD-Ib, presenting as single or multiple scattered deep round ulcers, inflammatory pseudo-polyps, obstructions, and strictures, which differ substantially from those in typical IBD. Distinct microbiota profiling and single-cell clustering of colonic mucosae in patients with GSD are conducted. Heterogeneous oral pathogenic enteric outgrowth induced by GSD is a potent inducer of gut microbiota immaturity and colonic macrophage accumulation. Specifically, a unique population of macrophages with high CCL4L2 expression is identified in response to pathogenic bacteria in the intestine. Hyper-activation of the CCL4L2-VSIR axis leads to increased expression of AGR2 and ZG16 in epithelial cells, which mediates the unique progression of IBD in GSD-Ib. Collectively, the microbiota-driven pathomechanism of IBD is demonstrated in GSD-Ib and revealed the active role of the CCL4L2-VSIR axis in the interaction between the microbiota and colonic mucosal immunity. Thus, targeting gut dysbiosis and/or the CCL4L2-VISR axis may represent a potential therapy for GSD-associated IBD.

Acute Kaempferol Stimulation Induces AKT Phosphorylation in HepG2 Cells.

Type 2 diabetes mellitus (T2DM) stands as a prevalent global public health issue caused by deficiencies in the action of insulin and/or insulin production. In the liver, insulin plays an important role by inhibiting hepatic glucose production and stimulating glycogen storage, thereby contributing to blood glucose regulation. Kaempferitrin (KP) and kaempferol (KM), flavonoids found in Bauhinia forficata, exhibit insulin-mimetic properties, showing promise in managing T2DM. In this study, we aimed to assess the potential of these compounds in modulating the insulin signaling pathway and/or glucose metabolism. Cell viability assays confirmed the non-cytotoxic nature of both compounds toward HepG2 cells at the concentrations and times evaluated. Theoretical molecular docking studies revealed that KM had the best docking pose with the IR β subunit when compared to the KP. Moreover, Langmuir monolayer evaluation indicated molecular incorporation for both KM and KP. Specifically, KM exhibited the capability to increase AKT phosphorylation, a key kinase in insulin signaling, regardless of insulin receptor (IR) activation. Notably, KM showed an additional synergistic effect with insulin in activating AKT. In conclusion, our findings suggest the potential of KM as a promising compound for stimulating AKT activation, thereby influencing energy metabolism in T2DM.

Youth Pitcher Fatigue: Medial Elbow Laxity, Ultrasonographic Assessment of Flexor-Pronator Mass Energy Depletion, and Association With Pitch Count.

Ulnar collateral ligament (UCL) injuries in youth pitchers continue to be concerning despite the institution of pitch count limits. Flexor-pronator mass fatigue can lead to diminished dynamic stability, resulting in greater stress on the UCL. To evaluate fatigue of the flexor-pronator mass by assessing changes in medial elbow laxity; noninvasively characterizing alterations in muscle glycogen; and identifying changes in subjective fatigue, strength, range of motion (ROM), pitching velocity, and accuracy with increasing pitches thrown by youth pitchers to their recommended 75-pitch count limit. It was hypothesized that, with increased pitches, medial elbow laxity would increase and that the glycogen content of the flexor-pronator mass would decrease. Descriptive laboratory study. Healthy male pitchers aged 10 years (n = 22) threw 3 sets of 25 pitches with 12 minutes between sets (3 timepoints). Bilateral ulnohumeral joint gapping was measured by applying a standardized valgus force and utilizing ultrasound imaging. Relative changes in muscle glycogen in the bilateral flexor carpi radialis (FCR), and the flexor digitorum superficialis/flexor carpi ulnaris (FDS/FCU) muscles were measured with ultrasound software and recorded as fuel percentiles. Additional measures obtained included subjective fatigue, strength, ROM, velocity, and accuracy. There were no differences in medial elbow joint-line gapping between the throwing and nonthrowing arms or between timepoints. The throwing arm demonstrated a significant decline in fuel percentile of the FCR from baseline to after 75 pitches (P = .05). There were no differences across timepoints for FDS/FCU fuel percentile values. Fatigue measurements for both arms were significantly higher at all timepoints compared with baseline (P≤ .03). Grip strength of the dominant arm after 75 pitches was decreased significantly compared with after 25 pitches (P = .02). Although an increase in medial elbow joint gapping was not demonstrated within the recommended 75 pitch count limit in 10-year-olds, a relative decrease in glycogen stores of the flexor-pronator mass did occur, as well as a decrease in grip strength, with increasing subjective fatigue. This study provides a foundation for further objective testing of physiologic changes that occur with pitching to better guide pitch count limits and improve the safety of young athletes.

Energy supply during nocturnal endurance flight of migrant birds: effect of energy stores and flight behaviour

BackgroundMigrating birds fly non-stop for hours or even for days. They rely mainly on fat as fuel complemented by a certain amount of protein. Studies on homing pigeons and birds flying in a wind-tunnel suggest that the shares of fat and protein on total energy expenditure vary with flight duration and body fat stores. Also, flight behaviour, such as descending flight, is expected to affect metabolism. However, studies on free flying migrant birds under natural conditions are lacking.MethodsOn a Swiss Alpine pass, we caught three species of nocturnal migrant passerines out of their natural migratory flight. Since most night migrants start soon after dusk, we used time since dusk as a measure of flight duration. We used plasma concentrations of metabolites of the fat, protein, and carbohydrate metabolism as indicators of relative fuel use. We used flight altitudes of birds tracked with radar and with atmospheric pressure loggers to characterize flight behaviour.ResultsThe indicators of fat catabolism (triglycerides, very low-density lipoproteins, glycerol) were positively correlated with body energy stores, supporting earlier findings that birds with high fat stores have a higher fat catabolism. As expected, plasma levels of triglycerides, very low-density lipoproteins, glycerol and ß-hydroxy-butyrate increased at the beginning of the night, indicating that nocturnal migrants increased their fat metabolism directly after take-off. Surprisingly, fat catabolism as well as glucose levels decreased in the second half of the night. Data from radar observations showed that the number of birds aloft, their mean height above ground and vertical flight speed decreased after midnight. Together with the findings from atmospheric pressure-loggers put on three species, this shows that nocturnal migrants migrating over continental Europe descend slowly during about 1.5 h before final landfall at night, which results in 11–30% energy savings according to current flight models.ConclusionsWe suggest that this slow descent reduces energy demands to an extent which is noticeable in the plasma concentration of lipid, protein, and carbohydrate metabolites. The slow descent may facilitate the search for a suitable resting habitat and serve to refill glycogen stores needed for foraging and predator escape when landed.

Chlorogenic Acid, a Potential Glucose-6-Phosphatase Inhibitor: An Approach to Develop a Pre-Clinical Glycogen Storage Disease Type I Model

Chlorogenic Acid, a Potential Glucose-6-Phosphatase Inhibitor: An Approach to Develop a Pre-Clinical Glycogen Storage Disease Type I Model

Modulation of Glucose Consumption and Uptake in HepG2 Cells by Aqueous Extracts from the Coelomic Fluid of the Edible Holothuria tubulosa Sea Cucumber.

The cell-free aqueous extract from the coelomic fluid of Holothuria tubulosa was prepared and examined for its glucose-lowering effect on HepG2 cells in vitro. In particular, employing a combination of cytochemical, flow cytometric, PCR, and protein blot techniques, we evaluated its role on glucose internalization and storage and on the upregulation and surface translocation of the two glucose transporters GLUT-2 and -4. The changes in expression, synthesis, and/or activation of the GLUT2-related transcription factor hepatocyte nuclear factor-1 alpha (HNF1α) and the GLUT-4-translocation regulatory factors insulin receptor substrate-1 (IRS-1) and AKT were also studied. Our results showed the improved glucose response by HepG2 cells, leading to an evident increase in glucose consumption/uptake and glycogen storage upon exposure. Moreover, the extract induced molecular reprogramming involving the upregulation of (i) IRS1 gene expression, (ii) the transcription and translation levels of HNF1α, AKT, and GLUT-4, (iii) the phosphorylation level of AKT, (iv) the synthesis of GLUT-2 protein, and (v) the translocation of GLUT-2 and -4 transporters onto the plasma membrane. Cumulatively, our results suggest that the coelomic fluid extract from H. tubulosa can be taken into consideration for the development of novel treatment agents against diabetes mellitus.

#1333 SGLT2 inhibitors as a treatment for Fanconi-Bickel syndrome: a case report

Abstract Background and Aims Fanconi-Bickel syndrome is an ultra-rare genetic disease characterized by SLC2A2 mutation encoding for the basolateral glucose transporter (GLUT2) in the proximal tubule of the nephron. This defective transport ultimately leads to accumulation of glycogen and dysfunction of proximal tubule cells. This manifests clinically as the renal Fanconi syndrome and eventually kidney failure. Systemic complications of proximal tubule injury include metabolic acidosis, bone demineralization and, for some not completely elucidated reasons, dysglycemia. Method We present the case of a 43-year-old man who was diagnosed with Fanconi-Bickel syndrome (homozygous splice site mutation in SLC2A2). He had a history of infantile-onset renal Fanconi syndrome, hypercalciuria and bilateral nephrolithiasis, osteoporosis, bilateral sensorineural deafness and non-insulin dependent type 2 diabetes. At referral the patient presented with CKD G2, non-anion gap metabolic acidosis, slightly elevated serum calcium, decreased serum phosphate, suppressed PTH and hypercalciuria (Table 1), despite oral supplementation of phosphate, bicarbonate and vitamin D. We hypothesized that SGLT2i in this patient may halt the progressive proximal tubule injury by preventive glucose uptake and help the management of diabetes. Results Fractional excretion of phosphate (FEPO4) and urinary retinol-binding protein (RBP)-creatinine ratio, two markers of proximal tubular injury, were stable after 2 months of SGLT2i therapy (Fig. 1). Conclusion To date, Fanconi-Bickel syndrome does not have a specific treatment. Standard of care includes supplements of fluids and electrolytes to counterbalance proximal tubular injury and management of complications such as diabetes. SGLT2i use has been described in a mouse model of another glycogen storage disease (GSD1b), whose underlying defect is different from that of Fanconi-Bickel but presents with a similar phenotype [2]. Data showed that gliflozins prevents glycogen accumulation and restores proximal tubule cells’ function. Using the same rationale, the administration of SGLT2i in adult patients with Fanconi-Bickel syndrome may prevent further proximal damage and slow the progression towards end-stage kidney disease. In conclusion, we hypothesize a potential benefit of SGLT2i in adult patients affected by Fanconi-Bickel syndrome.

Validating Well-Functioning Hepatic Organoids for Toxicity Evaluation.

"Organoids", three-dimensional self-organized organ-like miniature tissues, are proposed as intermediary models that bridge the gap between animal and human studies in drug development. Despite recent advancements in organoid model development, studies on toxicity using these models are limited. Therefore, in this study, we aimed to analyze the functionality and gene expression of pre- and post-differentiated human hepatic organoids derived from induced pluripotent stem cells and utilize them for toxicity assessment. First, we confirmed the functional similarity of this hepatic organoid model to the human liver through various functional assessments, such as glycogen storage, albumin and bile acid secretion, and cytochrome P450 (CYP) activity. Subsequently, utilizing these functionally validated hepatic organoids, we conducted toxicity evaluations with three hepatotoxic substances (ketoconazole, troglitazone, and tolcapone), which are well known for causing drug-induced liver injury, and three non-hepatotoxic substances (sucrose, ascorbic acid, and biotin). The organoids effectively distinguished between the toxicity levels of substances with and without hepatic toxicity. We demonstrated the potential of hepatic organoids with validated functionalities and genetic characteristics as promising models for toxicity evaluation by analyzing toxicological changes occurring in hepatoxic drug-treated organoids.

Synergism of dual AAV gene therapy and rapamycin rescues GSDIII phenotype in muscle and liver.

Glycogen storage disease type III (GSDIII) is a rare metabolic disorder due to glycogen debranching enzyme (GDE) deficiency. Reduced GDE activity leads to pathological glycogen accumulation responsible for impaired hepatic metabolism and muscle weakness. To date, there is no curative treatment for GSDIII. We previously reported that 2 distinct dual AAV vectors encoding for GDE were needed to correct liver and muscle in a GSDIII mouse model. Here, we evaluated the efficacy of rapamycin in combination with AAV gene therapy. Simultaneous treatment with rapamycin and a potentially novel dual AAV vector expressing GDE in the liver and muscle resulted in a synergic effect demonstrated at biochemical and functional levels. Transcriptomic analysis confirmed synergy and suggested a putative mechanism based on the correction of lysosomal impairment. In GSDIII mice livers, dual AAV gene therapy combined with rapamycin reduced the effect of the immune response to AAV observed in this disease model. These data provide proof of concept of an approach exploiting the combination of gene therapy and rapamycin to improve efficacy and safety and to support clinical translation.

Investigation on the treatment of empagliflozin in glycogen storage disease type Ib

Objective: To investigate the safety, efficacy and effective dose of empagliflozin in the treatment of glycogen storage disease type Ⅰb (GSD Ⅰb). Method: This was a cross sectional study. A total of 28 children with GSDⅠb who started oral empagliflozin treatment from January 2021 to June 2023 in the WeChat group of patients with glycogen storage disease were selected as the study objects. Clinical data such as general situation, current situation of medication and adverse reactions of the children were collected through questionnaires from June 18 to 30, 2023. The differences of symptoms and laboratory tests before and after empagliflozin treatment were compared by using paired chi-square test and Wilcoxon signed rank sum test. Results: Totally 28 children with GSD Ⅰb were from 12 different provinces, autonomous regions and municipalities in China. There were 14 males and 14 females, Empagliflozin treatment was started at the age of 4.8(2.4, 10.8) years, the time of treatment was 14.5(11.3, 21.5) months, the initial dosage was (0.23±0.11) mg/(kg·d), and the maintenance dosage was (0.28±0.12) mg/(kg·d). Empagliflozin showed positive effects on neutropenia, severity of inflammatory bowel disease like symptoms(Z=-3.70, -2.65, both P<0.05), The proportion of recurrent oral ulcers, recurrent bacterial infections and anemia was significantly lower than that before medication 18% (5/28) vs. (46% (13/28), 14% (4/28) vs. 46% (13/28), 21% (6/28) vs. 46% (13/28), χ²=4.05, 5.26, 3.05, all P<0.05). GCSF was once used in 5 children with GSD Ⅰb, all of them had completely stopped GCSF after empagliflozin treatment. The most common adverse events during empagliflozin treatment were hypoglycemia (5 children) and urinary infection (3 children). All 28 patients had no serious adverse reactions. Conclusions: Empagliflozin can increase the neutrophil count of children with GSD Ⅰb, and had a favorable effect on symptoms such as recurrent oral ulcers, and recurrent infection. The common adverse events during empagliflozin treatment were hypoglycemia and urinary infection.