Hepatic glycogen storage diseases are associated to microbial dysbiosis

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.

Micronutrient Deficiency in Inherited Metabolic Disorders Requiring Diet Regimen: A Brief Critical Review

Many inherited metabolic disorders (IMDs), including disorders of amino acid, fatty acid, and carbohydrate metabolism, are treated with a dietary reduction or exclusion of certain macronutrients, putting one at risk of a reduced intake of micronutrients. In this review, we aim to provide available evidence on the most common micronutrient deficits related to specific dietary approaches and on the management of their deficiency, in the meanwhile discussing the main critical points of each nutritional supplementation. The emerging concepts are that a great heterogeneity in clinical practice exists, as well as no univocal evidence on the most common micronutrient abnormalities. In phenylketonuria, for example, micronutrients are recommended to be supplemented through protein substitutes; however, not all formulas are equally supplemented and some of them are not added with micronutrients. Data on pyridoxine and riboflavin status in these patients are particularly scarce. In long-chain fatty acid oxidation disorders, no specific recommendations on micronutrient supplementation are available. Regarding carbohydrate metabolism disorders, the difficult-to-ascertain sugar content in supplementation formulas is still a matter of concern. A ketogenic diet may predispose one to both oligoelement deficits and their overload, and therefore deserves specific formulations. In conclusion, our overview points out the lack of unanimous approaches to micronutrient deficiencies, the need for specific formulations for IMDs, and the necessity of high-quality studies, particularly for some under-investigated deficits.

Gut microbiota in muscular atrophy development, progression, and treatment: New therapeutic targets and opportunities

Skeletal muscle atrophy is a debilitating condition that significantly affects quality of life and often lacks effective treatment options. Muscle atrophy can have various causes, including myogenic, neurogenic, and other factors. Recent investigation has underscored a compelling link between the gut microbiota and skeletal muscle. Discerning the potential differences in the gut microbiota associated with muscle atrophy-related diseases, understanding their influence on disease development, and recognizing their potential as intervention targets are of paramount importance. This review aims to provide a comprehensive overview of the role of the gut microbiota in muscle atrophy-related diseases. We summarize clinical and pre-clinical studies that investigate the potential for gut microbiota modulation to enhance muscle performance and promote disease recovery. Furthermore, we delve into the intricate interplay between the gut microbiota and muscle atrophy-related diseases, drawing from an array of studies. Emerging evidence suggests significant differences in gut microbiota composition in individuals with muscle atrophy-related diseases compared with healthy individuals. It is conceivable that these alterations in the microbiota contribute to the pathogenesis of these disorders through bacterium-related metabolites or inflammatory signals. Additionally, interventions targeting the gut microbiota have demonstrated promising results for mitigating disease progression in animal models, underscoring the therapeutic potential of modulating the gut microbiota in these conditions. By analyzing the available literature, this review sheds light on the involvement of the gut microbiota in muscle atrophy-related diseases. The findings contribute to our understanding of the underlying mechanisms and open avenues for development of novel therapeutic strategies targeting the gut-muscle axis.

Gut microbiota and pediatric patients with spina bifida and neurogenic bowel dysfunction

PURPOSE

Gut microbiota has recently been recognized to be influenced by a broad range of pathologies. Alterations of gut microbiota are known as dysbiosis and have found to be related to chronic constipation, a condition which affects also pediatric patients with spina bifida (SB).

METHODS

In this study, gut microbiota richness and composition were investigated by 16S rRNA sequencing and bioinformatic analysis in 48 SB patients (mean age, 11.9 ± 4.8 years) with secondary neurogenic constipation and 32 healthy controls (mean age, 18.0 ± 9.6 years). The study also aimed at exploring eventual effects of laxatives and transanal irrigation (TAI) adopted by SB subjects to get relief from the symptoms of neurogenic constipation.

RESULTS

Collected data demonstrated that the microbiota richness of SB patients was significantly increased compared to healthy controls, with a higher number of dominant bacteria rather than rare species. The absence of SB condition was associated with taxa Coprococcus 2, with the species C. eutactus and Roseburia, Dialister, and the [Eubacterium] coprostanoligenes group. On the other hand, the SB patients displayed a different group of positively associated taxa, namely, Blautia, Collinsella, Intestinibacter, and Romboutsia genera, the [Clostridium] innocuum group, and Clostridium sensu stricto 1. Bifidobacterium and the [Eubacterium] hallii group were also found to be positively associated with SB gut microbiome.

CONCLUSIONS

Among SB patients, the administration of laxatives and TAI did not negatively affect gut microbiota diversity and composition, even considering long-term use (up to 5 years) of TAI device.

Are the Bacteria and Their Metabolites Contributing for Gut Inflammation on GSD-Ia Patients?

Recently, patients with glycogen storage disease (GSD) have been described as having gut dysbiosis, lower fecal pH, and an imbalance in SCFAs due to an increase in acetate and propionate levels. Here, we report the fecal measurement of bacterial-related metabolites formic, acetic, lactic, propionic, and succinic acid, a key metabolite of both host and microbiota, on a previously described cohort of 24 patients (GSD Ia = 15, GSD Ib = 5, 1 GSD III = 1 and GSD IX = 3) and 16 healthy controls, with similar sex and age, using the high-performance liquid chromatography technique. The succinic acid levels were higher in the GSD patients than in the controls (patients = 38.02; controls = 27.53; p = 0.045), without differences between the groups for other metabolites. Fecal pH present inverse correlation with lactic acid (R = −0.54; p = 0.0085), while OTUs were inversely correlated with both lactic (R = −0.46; p = 0.026) and formic (R = −0.54; p = 0.026) acids. Using two distinct metrics of diversity, borderline significance was obtained for propionic acid, affecting the microbial structure on Euclidean basis in 8% (r² = 0.081; p = 0.079), and for lactic acid, affecting 6% of microbial structure using Bray–Curtis distance (r² = 0.065; p = 0.060). No correlation was found between SCFAs and total carbohydrate consumption among the participants or uncooked cornstarch consumption among the patients.

Special Diets in Infants and Children and Impact on Gut Microbioma

Gut microbiota is a complex system that starts to take shape early in life. Several factors influence the rise of microbial gut colonization, such as term and mode of delivery, exposure to antibiotics, maternal diet, presence of siblings and family members, pets, genetics, local environment, and geographical location. Breastfeeding, complementary feeding, and later dietary patterns during infancy and toddlerhood are major players in the proper development of microbial communities. Nonetheless, if dysbiosis occurs, gut microbiota may remain impaired throughout life, leading to deleterious consequences, such as greater predisposition to non-communicable diseases, more susceptible immune system and altered gut–brain axis. Children with specific diseases (i.e., food allergies, inborn errors of metabolism, celiac disease) need a special formula and later a special diet, excluding certain foods or nutrients. We searched on PubMed/Medline, Scopus and Embase for relevant pediatric studies published over the last twenty years on gut microbiota dietary patterns and excluded case reports or series and letters. The aim of this review is to highlight the changes in the gut microbiota in infants and children fed with special formula or diets for therapeutic requirements and, its potential health implications, with respect to gut microbiota under standard diets.

Clinical, pathological and molecular spectrum of patients with glycogen storage diseases in Pakistan

OBJECTIVES

Evaluation of clinical, biochemical and molecular analysis of Pakistani patients with hepatic GSDs.

METHODS

Medical charts, biochemical, histopathological and molecular results of patients with hepatic GSD were reviewed.

RESULTS

Out of 55 GSD patients, 41 (74.5%) were males and 14 (25.5%) were females with consanguinity in 50 (91%) patients. The median age of initial symptoms, clinic diagnosis and molecular diagnosis were 450 (IQR: 270-960), 1,095 (IQR: 510-1,825) and 1717 (IQR: 796-3,011) days, respectively. Molecular analysis and enzyme activity was available for 33 (60%) and two patients, respectively. GSD III (n=9) was most prevalent followed by GSD Ib (n=7), GSD IXc (n=6), GSD VI (n=4), GSD Ia (n=3), GSD XI (n=3), GSD IXb (n=2) and GSD IXa (n=1). In patients (n=33) who underwent molecular analysis; 19 different variants in eight genes associated with GSD were identified. We also report five novel variants, two in SLC37A4, one in AGL and two in PYGL contributing to the diagnosis of GSD Ib, GSD III and GSD VI, respectively.

CONCLUSIONS

Fifty-five patients of GSDs in 26 families from a single care provider indicate a relatively high frequency of GSD in Pakistan, with multiple unrelated families harboring identical disease-causing variants, on molecular analysis, including two known pathogenic variants in SLC37A4 and PHKG2, and a novel variant in AGL.

Glycogen Storage Disease Type Ia: Current Management Options, Burden and Unmet Needs

Glycogen storage disease type Ia (GSDIa) is caused by defective glucose-6-phosphatase, a key enzyme in carbohydrate metabolism. Affected individuals cannot release glucose during fasting and accumulate excess glycogen and fat in the liver and kidney, putting them at risk of severe hypoglycaemia and secondary metabolic perturbations. Good glycaemic/metabolic control through strict dietary treatment and regular doses of uncooked cornstarch (UCCS) is essential for preventing hypoglycaemia and long-term complications. Dietary treatment has improved the prognosis for patients with GSDIa; however, the disease itself, its management and monitoring have significant physical, psychological and psychosocial burden on individuals and parents/caregivers. Hypoglycaemia risk persists if a single dose of UCCS is delayed/missed or in cases of gastrointestinal intolerance. UCCS therapy is imprecise, does not treat the cause of disease, may trigger secondary metabolic manifestations and may not prevent long-term complications. We review the importance of and challenges associated with achieving good glycaemic/metabolic control in individuals with GSDIa and how this should be balanced with age-specific psychosocial development towards independence, management of anxiety and preservation of quality of life (QoL). The unmet need for treatment strategies that address the cause of disease, restore glucose homeostasis, reduce the risk of hypoglycaemia/secondary metabolic perturbations and improve QoL is also discussed.

Dysbiosis, Host Metabolism, and Non-communicable Diseases: Trialogue in the Inborn Errors of Metabolism

Inborn errors of metabolism (IEMs) represent a complex system model, in need of a shift of approach exploring the main factors mediating the regulation of the system, internal or external and overcoming the traditional concept of biochemical and genetic defects. In this context, among the established factors influencing the metabolic flux, i.e., diet, lifestyle, antibiotics, xenobiotics, infectious agents, also the individual gut microbiota should be considered. A healthy gut microbiota contributes in maintaining human health by providing unique metabolic functions to the human host. Many patients with IEMs are on special diets, the main treatment for these diseases. Hence, IEMs represent a good model to evaluate how specific dietary patterns, in terms of macronutrients composition and quality of nutrients, can be related to a characteristic microbiota associated with a specific clinical phenotype (“enterophenotype”). In the present review, we aim at reporting the possible links existing between dysbiosis, a condition reported in IEMs patients, and a pro-inflammatory status, through an altered “gut-liver” cross-talk network and a major oxidative stress, with a repercussion on the health status of the patient, increasing the risk of non-communicable diseases (NCDs). On this basis, more attention should be paid to the nutritional status assessment and the clinical and biochemical signs of possible onset of comorbidities, with the goal of improving the long-term wellbeing in IEMs. A balanced intestinal ecosystem has been shown to positively contribute to patient health and its perturbation may influence the clinical spectrum of individuals with IEMs. For this, reaching eubiosis through the improvement of the quality of dietary products and mixtures, the use of pre-, pro- and postbiotics, could represent both a preventive and therapeutic strategy in these complex diseases.

Bone Mineral Density in Patients with Hepatic Glycogen Storage Diseases

The association between bone mineral density (BMD) and hepatic glycogen storage diseases (GSDs) is still unclear. To evaluate the BMD of patients with GSD I, IIIa and IXα, a cross-sectional study was performed, including 23 patients (GSD Ia = 13, Ib = 5, IIIa = 2 and IXα = 3; median age = 11.9 years; IQ = 10.9–20.1) who underwent a dual-energy X-ray absorptiometry (DXA). Osteocalcin (OC, n = 18), procollagen type 1 N-terminal propeptide (P1NP, n = 19), collagen type 1 C-terminal telopeptide (CTX, n = 18) and 25-OH Vitamin D (n = 23) were also measured. The participants completed a 3-day food diary (n = 20). Low BMD was defined as a Z-score ≤ −2.0. All participants were receiving uncooked cornstarch (median dosage = 6.3 g/kg/day) at inclusion, and 11 (47.8%) presented good metabolic control. Three (13%) patients (GSD Ia = 1, with poor metabolic control; IIIa = 2, both with high CPK levels) had a BMD ≤ −2.0. CTX, OC and P1NP correlated negatively with body weight and age. 25-OH Vitamin D concentration was decreased in seven (30.4%) patients. Our data suggest that patients with hepatic GSDs may have low BMD, especially in the presence of muscular involvement and poor metabolic control. Systematic nutritional monitoring of these patients is essential.

Uncooked cornstarch for the prevention of hypoglycemic events

Hypoglycemia is a pathological condition characterized by a low plasma glucose concentration associated with typical autonomic and/or neuroglycopenic symptoms, and resolution of these symptoms with carbohydrate consumption. Hypoglycemia is quite common in clinical practice, particularly in insulin-treated patients with diabetes and in other inherited or acquired conditions involving the regulation of glucose metabolism. Beyond symptoms that might strongly affect the quality of life, hypoglycemia can lead to short- and long-term detrimental consequences for health. Hypoglycemia can be prevented by appropriate changes in dietary habits or by relevant modifications of the drug treatment. Several dietary approaches based on the intake of various carbohydrate foods have been tested for hypoglycemia prevention; among them uncooked cornstarch (UCS) has demonstrated a great efficacy. In this narrative review, we have summarized the current evidence on the UCS usefulness in some conditions characterized by high hypoglycemic risk, focusing on some inherited diseases -i.e. glycogen storage diseases and other rare disorders - and acquired conditions such as type 1 diabetes, postprandial hypoglycemia consequent to esophageal-gastric or bariatric surgery, and insulin autoimmune syndrome. We also considered the possible role of UCS during endurance exercise performance. Lastly, we have discussed the dose requirement, the side effects, the limitations of UCS use, and the plausible mechanisms by which UCS could prevent hypoglycemia.

Overview of the rules of the microbial engagement in the gut microbiome: a step towards microbiome therapeutics

Human gut microbiome is a diversified, resilient, immuno-stabilized, metabolically active and physiologically essential component of the human body. Scientific explorations have been made to seek in-depth information about human gut microbiome establishment, microbiome functioning, microbiome succession, factors influencing microbial community dynamics and the role of gut microbiome in health and diseases. Extensive investigations have proposed the microbiome therapeutics as a futuristic medicine for various physiological and metabolic disorders. A comprehensive outlook of microbial colonization, host-microbe interactions, microbial adaptation, commensal selection and immuno-survivability is still required to catalogue the essential genetic and physiological features for the commensal engagement. Evolution of a structured human gut microbiome relies on the microbial flexibility towards genetic, immunological and physiological adaptation in the human gut. Key features for commensalism could be utilized in developing tailor-made microbiome-based therapy to overcome various physiological and metabolic disorders. This review describes the key genetics and physiological traits required for host-microbe interaction and successful commensalism to institute a human gut microbiome.

Genotypic and clinical analysis of 49 Chinese children with hepatic glycogen storage diseases

BACKGROUND

Glycogen storage disease (GSD) is a relatively rare inborn metabolic disorder, our study aims to investigate the genotypic and clinical feature of hepatic GSDs in China.

METHODS

The clinical and genotypic data of 49 patients with hepatic GSDs were collected retrospectively and analyzed.

RESULTS

After gene sequencing, 49 patients were diagnosed as GSDs, including GSD Ia (24 cases), GSD IIIa (11 cases), GSD IXa (8 cases), GSD VI (3 cases) and GSD Ib (3 cases). About 45 gene variants of G6PC, AGL, PHKA2, PYGL, and SLC37A4 were detected; among which, 22 variants were unreported previously. c.648G>T (p. Leu216Leu) of G6PC exon 5 is the most common variant for GSD Ia patients (20/24,83.33%）, splice variant c.1735+1G>T of AGL exon 13 is relatively common among GSD IIIa, while novel variant accounts for the majority of GSD IXa and GSD VI patients. As for clinical features, there was no significant difference in the onset age among group GSD Ia, GSD IIIa, and GSD IXa, but the age at diagnosis and average disease duration from diagnosis of GSD Ia were significantly higher than GSD IIIa and GSD IXa. Body weight of GSD patients was basically normal, but growth retardation was relatively common among them, especially for GSD Ia patients; and renomegaly was only found in GSD Ia. Besides, serum cholesterol, triglyceride, lactic acid, and uric acid in GSD Ia were significantly higher than those with GSD IIIa and IXa (p < 0.05); but ALT, AST, CK, and LDH of GSD III and GSD IXa were significantly higher when compared to GSD Ia (p < 0.05).

CONCLUSIONS

All hepatic GSDs patients share similarity in clinical and biochemical spectrum, but delayed diagnosis and biochemical metabolic abnormalities were common in GSD Ia. For family with GSD proband, pedigree analysis and genetic testing is strongly recommended.

Proteobacteria Overgrowth and Butyrate-Producing Taxa Depletion in the Gut Microbiota of Glycogen Storage Disease Type 1 Patients

A life-long dietary intervention can affect the substrates’ availability for gut fermentation in metabolic diseases such as the glycogen-storage diseases (GSD). Besides drug consumption, the main treatment of types GSD-Ia and Ib to prevent metabolic complications is a specific diet with definite nutrient intakes. In order to evaluate how deeply this dietary treatment affects gut bacteria, we compared the gut microbiota of nine GSD-I subjects and 12 healthy controls (HC) through 16S rRNA gene sequencing; we assessed their dietary intake and nutrients, their microbial short chain fatty acids (SCFAs) via gas chromatography and their hematic values. Both alpha-diversity and phylogenetic analysis revealed a significant biodiversity reduction in the GSD group compared to the HC group, and highlighted profound differences of their gut microbiota. GSD subjects were characterized by an increase in the relative abundance of Enterobacteriaceae and Veillonellaceae families, while the beneficial genera Faecalibacterium and Oscillospira were significantly reduced. SCFA quantification revealed a significant increase of fecal acetate and propionate in GSD subjects, but with a beneficial role probably reduced due to unbalanced bacterial interactions; nutritional values correlated to bacterial genera were significantly different between experimental groups, with nearly opposite cohort trends.

Dietary Management of the Glycogen Storage Diseases: Evolution of Treatment and Ongoing Controversies

The hepatic glycogen storage diseases (GSDs) are a group of disorders where abnormal storage or release of glycogen leads to potentially life-threatening hypoglycemia and metabolic disturbances. Dietary interventions have markedly improved the outcome for these disorders, from a previously fatal condition to one where people can do well with proper care. This article chronicles the evolution of dietary management and treatment of the hepatic GSDs (types 0, I, III, VI, IX, and XI). We examine historic and current approaches for preventing hypoglycemia associated with GSDs. There is a lack of consensus on the optimal dietary management of GSDs despite decades of research, and the ongoing controversies are discussed.