Finding balance between mature and immature neutrophils: The effects of empagliflozin in GSD-Ib

Dapagliflozin and Empagliflozin in Paediatric Indications: A Systematic Review

INTRODUCTION

In adults, sodium-glucose cotransporter type 2 inhibitors have revolutionised the treatment of type 2 diabetes mellitus, heart failure, and chronic kidney disease.

OBJECTIVE

We aimed to review information on compassionate use, clinical pharmacology, efficacy, and safety of dapagliflozin and empagliflozin in children.

METHODS

We conducted a systematic review of published clinical trials, case reports, and observational studies in Medline, Excerpta Medica, and Web of Science databases from inception to September 2023. For the two randomised controlled trials on type 2 diabetes mellitus (T2DM), we implemented a meta-analysis on the primary outcome (mean difference in glycosylated haemoglobin [HbA1c] between intervention and placebo groups). Review Manager (RevMan), version 5.4.1, was used for this purpose.

RESULTS

Thirty-five articles (nine case reports, ten case series, one prospective non-controlled trial, four controlled randomised trials, two surveys, six pharmacokinetic studies, and three pharmacovigilance studies) were selected, in which 415 children were exposed to either dapagliflozin or empagliflozin: 189 diabetic patients (mean age 14.7 ± 2.9 years), 32 children with glycogen storage disease type Ib (GSD Ib), glucose-6-phosphatase catalytic subunit 3 (G6PC3) deficiency, or severe congenital neutropenia type 4 (8.5 ± 5.1 years), 47 children with kidney disease or heart failure (11.2 ± 6.1 years), 84 patients in pharmacokinetic studies (15.1 ± 2.3 years), and 63 patients in toxicological series. The effect of dapagliflozin and empagliflozin in T2DM was demonstrated by HbA1c reduction in two randomised trials among a total of 177 adolescents, with a mean HbA1c difference of -0.82% (95% confidence interval -1.34 to -0.29) as compared to placebo (no heterogeneity, I2 = 0%). Dosage ranged between 5 and 20 mg (mean 11.4 ± 3.7) once daily for dapagliflozin and between 5 and 25 mg (mean 15.4 ± 7.4) once daily for empagliflozin. Among the paediatric cases of GSD Ib, empagliflozin 0.1-1.3 mg/kg/day improved neutropenia, infections, and gastrointestinal health. Dapagliflozin (mean dosage 6.9 ± 5.2 mg once daily) was well-tolerated in children with chronic kidney disease and heart failure. Side effects were generally mild, the most frequent being hypoglycaemia in children with GSD Ib (33% of patients) or T2DM (14% of patients) on concomitant hypoglycaemic drugs. Diabetic ketoacidosis is rare in children.

CONCLUSION

Early evidence suggests that dapagliflozin and empagliflozin are well tolerated in children. A clinical pharmacology rationale currently exists only for adolescents with diabetes mellitus.

PROSPERO REGISTRATION NUMBER

CRD42023438162.

DBS are suitable for 1,5-anhydroglucitol monitoring in GSD1b and G6PC3-deficient patients taking SGLT2 inhibitors to treat neutropenia

Glycogen storage disease type Ib (GSD1b) and G6PC3-deficiency are rare autosomal recessive diseases caused by inactivating mutations in SLC37A4 (coding for G6PT) and G6PC3, respectively. Both diseases are characterized by neutropenia and neutrophil dysfunction due to the intracellular accumulation of 1,5-anhydroglucitol-6-phosphate (1,5-AG6P), a potent inhibitor of hexokinases. We recently showed that the use of SGLT2 inhibitor therapy to reduce tubular reabsorption of its precursor, 1,5-anhydroglucitol (1,5-AG), a glucose analog present in blood, successfully restored the neutropenia and neutrophil function in G6PC3-deficient and GSD1b patients. The intra-individual variability of response to the treatment and the need to adjust the dose during treatment, especially in pediatric populations, can only be efficiently optimized if the concentration of 1,5-AG in blood is monitored during treatment, together with the patients' clinical signs and symptoms. Monitoring the 1,5-AG levels would be greatly simplified if it could be performed on dry blood spots (DBS) which are easy to collect, store and transport. The challenge is to know if a suitable method can be developed to perform accurate and reproducible assays for 1,5-AG using DBS. Here, we describe and validate an assay that quantifies 1,5-AG in DBS using isotopic dilution quantitation by LC-MS/MS that should greatly facilitate patients' follow-up. 1,5-AG levels measured in plasma and DBS give comparable values. This assay was used to monitor the levels of 1,5-AG in DBS from 3 G6PC3-deficient and 6 GSD1b patients during treatment with SGLT2 inhibitors. We recommend this approach to verify the adequate therapeutical response and compliance to the treatment in G6PC3-deficient and GSD1b patients treated with SGLT2 inhibitors.

Crohn-like disease long remission in a pediatric patient with glycogen storage disease type Ib treated with empagliflozin: a case report

Glycogen storage disease type Ib (GSD Ib) is a rare hereditary glycogen disorder that results in inadequate maintenance of glucose homeostasis, accumulation of glycogen in different organs, loss and dysfunction of neutrophils. Crohn's-like disease is observed in up to 24-77% of GDS Ib cases. Recently, empagliflozin has been recommended as a treatment for neutrophil dysfunction in GDS Ib patients with or without Crohn's-like disease. There are no guidelines for the treatment of inflammatory bowel disease (IBD) manifestation in GSD Ib patients, although some cases have been treated with granulocyte colony-stimulating factor and others with IBD conventional therapy, resulting in partial IBD remission. Herein, we describe a child with GDS Ib and Crohn's-like disease who was treated with empagliflozin and achieved complete remission after 2 years of treatment. This case is the first one with such a long follow-up evaluation including endoscopic and magnetic resonance enterography assessment. Our clinical evidence of remission of IBD manifestation in our GSD Ib patient and the role of neutrophils in GDS Ib described in the literature suggest a strong association with IBD pathophysiology and neutrophil function. The use of empagliflozin resulted in significant improvements in gastrointestinal symptoms, reduced drug usage, and enhanced quality of life in the patient, with a favorable safety profile, offering a promising new therapeutic option for this population.

Treatment of the Neutropenia Associated with GSD1b and G6PC3 Deficiency with SGLT2 Inhibitors

Glycogen storage disease type Ib (GSD1b) is due to a defect in the glucose-6-phosphate transporter (G6PT) of the endoplasmic reticulum, which is encoded by the SLC37A4 gene. This transporter allows the glucose-6-phosphate that is made in the cytosol to cross the endoplasmic reticulum (ER) membrane and be hydrolyzed by glucose-6-phosphatase (G6PC1), a membrane enzyme whose catalytic site faces the lumen of the ER. Logically, G6PT deficiency causes the same metabolic symptoms (hepatorenal glycogenosis, lactic acidosis, hypoglycemia) as deficiency in G6PC1 (GSD1a). Unlike GSD1a, GSD1b is accompanied by low neutrophil counts and impaired neutrophil function, which is also observed, independently of any metabolic problem, in G6PC3 deficiency. Neutrophil dysfunction is, in both diseases, due to the accumulation of 1,5-anhydroglucitol-6-phosphate (1,5-AG6P), a potent inhibitor of hexokinases, which is slowly formed in the cells from 1,5-anhydroglucitol (1,5-AG), a glucose analog that is normally present in blood. Healthy neutrophils prevent the accumulation of 1,5-AG6P due to its hydrolysis by G6PC3 following transport into the ER by G6PT. An understanding of this mechanism has led to a treatment aimed at lowering the concentration of 1,5-AG in blood by treating patients with inhibitors of SGLT2, which inhibits renal glucose reabsorption. The enhanced urinary excretion of glucose inhibits the 1,5-AG transporter, SGLT5, causing a substantial decrease in the concentration of this polyol in blood, an increase in neutrophil counts and function and a remarkable improvement in neutropenia-associated clinical signs and symptoms.

Neutrophil aging exacerbates high fat diet induced metabolic alterations

BACKGROUND

High fat diet (HFD) chronically hyper-activate the myeloid cell precursors, but whether it affects the neutrophil aging is unknown.

PURPOSE

We characterized how HFD impacts neutrophil aging, infiltration in metabolic tissues and if this aging, in turn, modulates the development of metabolic alterations. We immunophenotyped neutrophils and characterized the metabolic responses in physiology (wild-type mice, WT) and in mice with constitutively aged neutrophils (MRP8 driven conditional deletion of CXCR4; herein CXCR4fl/flCre+) or with constitutively fresh neutrophils (MRP8 driven conditional deletion of CXCR2; CXCR2fl/flCre+), following 20 weeks of HFD feeding (45 % kcal from fat).

FINDINGS

After 20 weeks HFD, the gluco-metabolic profile of CXCR4fl/flCre+ mice was comparable to that of WT mice, while CXCR2fl/flCre+ mice were protected from metabolic alterations. CXCR4fl/flCre+ infiltrated more, but CXCR2fl/flCre+ neutrophils infiltrated less, in liver and visceral adipose tissue (VAT). As consequence, while CXCR4fl/flCre+ resulted into hepatic "suicidal" neutrophils extracellular traps (NETs) and altered immune cell architecture in VAT, CXCR2fl/flCre+ promoted proresolutive hepatic NETs and reduced accumulation of pro-inflammatory macrophages in VAT. In humans, higher Cxcl12 (CXCR4 ligand) plasma levels correlated with visceral adiposity while higher levels of Cxcl1, the ligand of CXCR2, correlated with indexes of hepatic steatosis, adiposity and metabolic syndrome.

CONCLUSIONS

Neutrophil aging might contribute to the development of HFD induced metabolic disorders.

The High Fat Diet Impacts the Plasticity between Fresh and Aged Neutrophils

Metabolic alterations induced by unhealthy lifestyles, including obesity and insulin resistance are often associated with increased innate immune response and chronic inflammation. Cholesterol has been identified as a key metabolite driving the activation of the inflammasome and the "epigenetic memory" in long-term living hematopoietic stem cells. In addition to these mechanisms, the physiological aging of short-living neutrophils is a relevant modifier of their immune competency, as while they egress from medullary niches as "fresh", fully competent, cells, they turn into "aged", disarmed cells, when they extravasate into peripheral tissues to fight against pathogens or they reach the spleen for disposal. We recently observed that cardio-metabolic alterations induced by a lipid enriched unhealthy diet critically accelerate this process. Indeed, the chronic feeding with a high fat diet (HFD) results in the increase of aged neutrophils in the circulation and their accumulation in liver. This profile is associated with a deteriorated insulin response and obesity. The HFD primes aged, but not fresh neutrophils, to infiltrate in the liver and promotes inflammation coupled to altered cell immune architecture in visceral adipose tissue. Preventing the aging of neutrophils via selective ablation of CXCR2, reduces the development of obesity and improves the sensitivity to insulin. In humans, plasma levels of CXCL1, one of the cytokines binding CXCR2 and promoting neutrophil aging, are directly associated with abdominal adiposity and fatty liver independently of other risk factors. Together these findings point to a direct role of aged neutrophils in the development of metabolic disorders.