Substrate Reduction Research Articles

Fabry Disease: Current and Novel Therapeutic Strategies. A Narrative Review.

Fabry disease (FD) is an inherited lysosomal storage disorder, leading to multisystemic manifestations and causing significant morbidity and mortality. The aim of this narrative review is to present the current and novel therapeutic strategies in FD, including symptomatic and specific treatment options. A systematic literature search was conducted to identify relevant studies, including completed and ongoing randomized-controlled clinical trials (RCTs), prospective or retrospective cohort studies, case series and case reports that provided clinical data regarding FD treatment. A multidisciplinary symptomatic treatment is recommended for FD patients, personalized according to disease manifestations and their severity. During the last two decades, FD-specific treatments, including two enzyme-replacement-therapies (agalsidase alfa and agalsidase beta) and chaperone treatment with migalastat have been approved for use and allowed for symptoms' stabilization or even disease burden reduction. More therapeutic agents are currently under investigation. Substrate reduction therapies, including lucerastat and venglustat, have shown promising results in RCTs and may be used either as monotherapy or as complementary therapy to established enzymereplacement- therapies. More stable enzyme-replacement-therapy molecules that are associated with less adverse events and lower likelihood of neutralizing antibodies formation have also been developed. Ex-vivo and in-vivo gene therapy is being tested in animal models and pilot human clinical trials, with preliminary results showing a favorable safety and efficacy profile. The therapeutic landscape in FD appears to be actively expanding with more treatment options expected to become available in the near future, allowing for a more personalized approach in FD patients.

Substrate reduction therapy for Morquio syndrome type A: An evaluation

Substrate reduction therapy for Morquio syndrome type A: An evaluation

ELIKIDS: Baseline characteristics from the eliglustat substrate reduction therapy trial in children with Gaucher disease type 1 or type 3

ELIKIDS: Baseline characteristics from the eliglustat substrate reduction therapy trial in children with Gaucher disease type 1 or type 3

Towards a substrate reduction therapy for metachromatic leukodystrophy

Towards a substrate reduction therapy for metachromatic leukodystrophy

Highly phosphorylated β-glucocerebrosidase (M011) has much broader tissue targeting and superior substrate reduction with potential for alternative dosing strategies for the treatment of Gaucher disease type I

Highly phosphorylated β-glucocerebrosidase (M011) has much broader tissue targeting and superior substrate reduction with potential for alternative dosing strategies for the treatment of Gaucher disease type I

Gene therapy for lysosomal storage diseases: Current clinical trial prospects.

Lysosomal storage diseases (LSDs) are a group of metabolic inborn errors caused by defective enzymes in the lysosome, resulting in the accumulation of undegraded substrates. LSDs are progressive diseases that exhibit variable rates of progression depending on the disease and the patient. The availability of effective treatment options, including substrate reduction therapy, pharmacological chaperone therapy, enzyme replacement therapy, and bone marrow transplantation, has increased survival time and improved the quality of life in many patients with LSDs. However, these therapies are not sufficiently effective, especially against central nerve system abnormalities and corresponding neurological and psychiatric symptoms because of the blood-brain barrier that prevents the entry of drugs into the brain or limiting features of specific treatments. Gene therapy is a promising tool for the treatment of neurological pathologies associated with LSDs. Here, we review the current state of gene therapy for several LSDs for which clinical trials have been conducted or are planned. Several clinical trials using gene therapy for LSDs are underway as phase 1/2 studies; no adverse events have not been reported in most of these studies. The administration of viral vectors has achieved good therapeutic outcomes in animal models of LSDs, and subsequent human clinical trials are expected to promote the practical application of gene therapy for LSDs.

Management, vaccination status and COVID-19 morbidity of patients with Gaucher disease in Germany during the COVID-19 pandemic.

Continuation of standard management of Gaucher disease (GD) has been challenging during the COVID-19 pandemic, resulting in infrequent/missed infusions and follow-up appointments. Little data are available on the consequences of these changes and on the SARS-CoV-2 vaccinations in German GD patients. A survey with 22 questions about GD management during the pandemic was sent to 19 German Gaucher centres. It was answered by 11/19 centres caring for 257 GD patients (almost ¾ of the German GD population); 245 patients had type 1 and 12 had type 3 GD; 240 were ≥ 18 years old. Monitoring intervals were prolonged in 8/11 centres from a median of 9 to 12 months. Enzyme replacement therapy (ERT) was changed to home ERT in 4 patients and substituted by oral substrate reduction therapy (SRT) in 6 patients. From March 2020 to October 2021, no serious complications of GD were documented. Only 4 SARS-CoV-2 infections were reported (1.6%). Two infections were asymptomatic and two mild; all occurred in adult type 1, non-splenectomized patients on ERT. Vaccination rate in adult GD was 79.5% (95.3% mRNA vaccines). Serious vaccination complications were not reported. The COVID-19 pandemic has lowered the threshold for switching from practice- or hospital-based ERT to home therapy or to SRT. No major GD complication was documented during the pandemic. Infection rate with SARS-CoV-2 in GD may rather be lower than expected, and its severity is mild. Vaccination rates are high in GD patients and vaccination was well tolerated.

Enhancement of fruit byproducts through bioconversion by Hermetia illucens (Diptera: Stratiomyidae).

Bioconversion is a biological process by which organic materials are converted into products with higher biological and commercial value. During its larval stage the black soldier fly Hermetia illucens is extremely voracious and can feed on a wide variety of organic materials. To study the impact of different fruit byproducts on the insect's growth, final larval biomass, substrate reduction, bioconversion parameters, and larval nutritional composition, 10 000 black soldier fly larvae (BSFL) were reared on 7.0 kg of one of three substrates (strawberry, tangerine, or orange) or on a standard diet as a control. The results highlight that BSFL can successfully feed and grow on each of these diets, though their development time, growth rate, and final biomass were differently impacted by the substrates, with strawberry being the most suitable. The lipid and protein contents of BSFL were similar among larvae fed on different substrates; however, major differences were detected in ash, micronutrient, fiber, fatty acid, and amino acid contents. Overall, the results indicate that fruit waste management through the BSFL bioconversion process represents a commercially promising resource for regional and national agrifood companies. Our study offers new perspectives for sustainable and environmentally friendly industrial development by which fruit byproducts or waste might be disposed of or unconventionally enhanced to create secondary products of high biological and economic value, including BSFL biomass as animal feed or, in perspective, as alternative protein source for human nutrition.

Influence of fruits and vegetable waste pre-treatment on black soldier fly larval growth

Hermetia illuciens, commonly known as black soldier fly (BSF) can convert organic biomass into manure and insect biomass into protein and fat. Currently, in the waste management industry, BSF larvae are predominantly used to convert valorized organic substrates into fertilizer and to produce biogas. They are also alternatively used as viable protein substitutes for animal feed as well as human consumer products. The treatment of organic wastes before BSFL consumption indicated a positive stimulation in the biomass conversion rate, larval growth rate and overall larval performance parameters. The current study was designed to analyze the effect of the bio-stimulation-based pre-treatment strategy of the feed on performance parameters, such as larval weight, larval survival rate, substrate reduction by pre-treatment of biowaste for better growth, efficient performance, and good biomass composition in BSFL. In our study, we noticed significant up- and downregulation of several larval parameters by assessing substrate composition, larval growth parameters and substrate reduction rate. The bio-stimulated waste showed larval weight gain when compared to larvae grown in control feed. The heat pretreated waste was not suitable for larval growth as the parameters assessed were observed to be declined. Further investigations are needed to comprehend how BSFL reared on pretreated substrates enhances the nutritional composition of larvae.

Maximizing hydrogen utilization efficiency in tandem hydrogenation of nitroarenes with ammonia borane

Tandem catalysis involving simultaneous dihydrogen generation from a hydrogen carrier and substrate reduction on a heterogeneous catalyst provides unique opportunities for green chemistry synthesis under mild reaction conditions.

Chapter 28 - Lysosomal storage disorders: Clinical and therapeutic aspects

The lysosomal storage disorders are hereditary metabolic disorders characterized by autosomal recessive inheritance, mainly caused by deficiency of an enzyme responsible for the intra-lysosomal breakdown of various substrates and products of cellular metabolism. This chapter examines the underlying defects, clinical manifestations, and provides context for the expected clinical outcome of various available therapy options employing enzyme replacement therapy, hematopoietic stem cell transplantation, substrate reduction, and enzyme enhancement therapies.

In vitro substrate reduction, chaperone and immunomodulation treatments reduce heparan sulfate in mucolipidosis III human fibroblasts.

Mucolipidosis II and III (MLII and MLIII) are autosomal recessive diseases caused by pathogenic variants in GNPTAB and GNPTG genes that lead to defects in GlcNAc-1-phosphotransferase. This enzyme adds mannose 6-phosphate residues to lysosomal hydrolases, which allows enzymes to enter lysosomes. Defective GlcNAc-1-phosphotransferase causes substrate accumulation and inflammation. These diseases have no treatment, and we hypothesized that the use of substrate reduction therapy and immunomodulation may be beneficial at the cell level and as a future therapeutic approach. Fibroblasts from two patients with MLIII alpha/beta and 2 patients with MLIII gamma as well as from one healthy control were treated with 10 µM miglustat, 20 µM genistein, and 20 µM thalidomide independently. ELISA assay and confocal immunofluorescence microscopy were used to evaluate the presence of heparan sulfate (HS) and the impact on substrate accumulation. ELISA assay showed HS reduction in all patients with the different treatments used (p=0.05). HS reduction was also observed by immunofluorescence microscopy. Our study produced encouraging results, since the reduction in substrate accumulation, even partial, may offer benefits to the phenotype of patients with inborn errors of metabolism.

Role of Partial Splenectomy in Gaucher's Disease in Resource Challenged Nations.

Gaucher's disease (GD) is a rare inherited metabolic disorder caused by the defective activity of glucocerebrosidase. Enzyme replacement therapy (ERT) and substrate reduction therapy are the treatment of choice. Total splenectomy has a role when the child develops complications of massive splenomegaly. There are only a few case series of partial splenectomy in GD in the pediatric age group. To study the role, technical feasibility, and challenges of partial splenectomy in children with GD with hypersplenism. Retrospective review of children of GD who had partial splenectomy between February 2016 and April 2018. Demographics, clinical findings, laboratory, operative details, transfusion requirements, and perioperative, immediate, and late complications were retrieved. Clinical courses after discharge were obtained from follow-up data. Eight children with GD underwent partial splenectomy between 2016 and 2018. The median age at surgery was 3 years and 6 months (range -2 years to 8 years). Five children underwent partial splenectomy successfully, of which one child required postoperative ventilatory support for 48 h owing to lung atelectasis. Three children underwent completion splenectomy due to bleed from the cut surface of the splenic remnant. One of the children who underwent completion splenectomy expired on the postoperative day 5 due to refractory shock with multi-organ dysfunction. Partial splenectomy has a definite role in selected children who present with massive splenomegaly with mechanical effects and/or hypersplenism while awaiting ERT.

Electrochemical experiments define potentials associated with binding of substrates and inhibitors to nitrogenase MoFe protein.

Nitrogenases catalyse the 6-electron reduction of dinitrogen to ammonia, passing through a series of redox and protonation levels during catalytic substrate reduction. The molybdenum-iron nitrogenase is the most well-studied, but redox potentials associated with proton-coupled transformations between the redox levels of the catalytic MoFe protein have proved difficult to pin down, in part due to a complex electron-transfer pathway from the partner Fe protein, linked to ATP-hydrolysis. Here, we apply electrochemical control to the MoFe protein of Azotobacter vinelandii nitrogenase, using europium(III/II)-ligand couples as low potential redox mediators. We combine insight from the electrochemical current response with data from gas chromatography and in situ infrared spectroscopy, in order to define potentials for the binding of a series of inhibitors (carbon monoxide, methyl isocyanide) to the metallo-catalytic site of the MoFe protein, and the onset of catalytic transformation of alternative substrates (protons and acetylene) by the enzyme. Thus, we associate potentials with the redox levels for inhibition and catalysis by nitrogenase, with relevance to the elusive mechanism of biological nitrogen fixation.

The new horizons for treatment of Late-Onset Pompe Disease (LOPD)

Late-onset Pompe disease (LOPD) is a genetic myopathy causing skeletal muscle weakness and severe respiratory impairment, due to the deficiency of the lysosomal enzyme acid alpha-glucosidase (GAA) leading to lysosomal glycogen accumulation along with other complex pathophysiological processes. A major step for treatment of Pompe disease was reached in 2006 with the marketing of alglucosidase alfa, a first enzyme replacement therapy (ERT) that showed a significant motor and respiratory benefit. However, efficacy of alglucosidase alfa is limited in LOPD with a loss of efficacy over time, promoting research on new treatments. Next-generation ERT are new enzymes biochemically modified to increase the uptake of exogenous enzyme by target tissues, and the benefit of two recombinant enzymes (avalglucosidase alfa and cipaglucosidase alfa) has been recently studied in large phase III clinical trials, the latest combined with miglustat. Several innovative therapies, based on GAA gene transfer, antisense oligonucleotides or inhibition of glycogen synthesis with substrate reduction therapy, are currently under study, but are still at an early stage of development. Overall, active research for new treatments raises hope for LOPD patients but challenges remain for the clinician with the need for reliable efficacy assessment tools, long-term registry data, and evidence-based recommendations for the best use of these new molecules recently available or under development.

Growth and Development of Black Soldier Fly (Hermetia illucens (L.), Diptera: Stratiomyidae) Larvae Grown on Carbohydrate, Protein, and Fruit-Based Waste Substrates

There has been a surge in interest in using food waste (FW) as an insect-rearing substrate in recent years. We examine the effect of protein-based food waste (leftover boneless chicken, LBC), carbohydrate-based food waste (overnight rice, OR), and fruit-based food waste (rotten banana, RB) on the following parameters: substrate reduction (SR), waste reduction index (WRI), bioconversion rate (BCR) and relative growth rate (RGR). BSFL reared on OR feed substrate had the highest biomass (0.23±0.01) g at d9 followed by RB (0.22±0.00) g and LBC (0.16±0.00) g. Larvae from OR-fed BSFL were the longest, averaging 20.53±0.46 mm in length on d12. The SR calculated for all feed substrates were as followed: RB (95.35 ± 0.33)% > OR (85.29 ± 0.80)% > LBC (83.17 ± 0.27)%. The WRI for control (C) and BSFL-fed on all feeds were in the following manner: (RBC:8.90±0.00 g days-1, RBBSFL:9.53±0.00 g days-1) > (ORC:7.35±0.00 g days-1, ORBSFL:8.53±0.09 g days-1) > (LBCC:6.90±0.00 g days-1, LBCBSFL: 8.32±0.03 g days-1). OR-fed BSFL showed the highest BCR (76.0±1.0) % and RGR (0.32±0.01) days-1. The FW’s self-composting (as in control) influenced the BSFL’s SR and WRI in all diets. Overall, the BSFL’s growth and development are affected by the nature, quality, and type of diet of the feed substrates.

Murine Fibroblasts and Primary Hepatocytes as Tools When Studying the Efficacy of Potential Therapies for Mucopolysaccharidosis Type I

Mucopolysaccharidosis type I (MPS I) is a metabolic genetic disease caused by the deficiency of a lysosomal enzyme involved in glycosaminoglycans (GAGs) degradation. MPS I cells have a constant level of GAG synthesis, but disturbed degradation means that GAGs accumulate progressively, impairing cell metabolism. GAG metabolism can be modulated by flavonoids, and these are being studied as therapeutics for MPS. We have optimised the protocol for obtaining fibroblasts and hepatocytes from the MPS I murine model and characterised the cells for their suitability as an in vitro model for testing compounds with therapeutic potential. Methods: Murine primary hepatocytes and fibroblasts were used as a cellular model to study the effect of genistein, biochanin A, and kaempferol on the modulation of the GAG synthesis process. Flavonoids were used individually as well as in two-component mixtures. There were no statistically significant differences in GAG synthesis levels from cell types obtained from either wild-type or MPS I mice. We also showed that MPS I fibroblasts and hepatocytes store GAGs, which makes them useful in vitro models for testing the effectiveness of substrate reduction therapies. Furthermore, tested flavonoids had a different impact on GAG synthesis depending on cell type and whether they were used alone or in a mixture. The tested flavonoids reduce GAG synthesis more effectively in fibroblasts than in hepatocytes, regardless of whether they are used individually or in a mixture. Flavonoids modulate the level of GAG synthesis differently depending on cell types, therefore in vitro experiments performed to assess the effectiveness of potential therapies for metabolic diseases should be carried out using more than one cell model, and only such an approach will allow for full answering scientific questions.

Biological Pretreatment Effects on the Bioconversion of Brewer Spent Grain with Hermetia illucens Larvae

Hermetia illucens is an important species for waste management and the circular economy. The aim of this study was to analyze the effects of Trichoderma reesei C2A and Pleurotus sp. as pretreatments of brewer spent grain (BSG). BSG was inoculated with fungal solution or distilled water (control). After seven days, this was used for H. illucens larvae cultivation. At the end of bioconversion process, parameters of substrate reduction and H. illucens larval development were evaluated. Chemical properties of BSG, frass and larvae were also analyzed. With T. reesei C2A pretreatment, highest substrate reduction (46.3 ± 0.9%) was achieved, but larval growth rate was lower (1.0 ± 0.1 mg/d) than that of control (2.8 ± 0.2 mg/d). Larvae of Pleurotus sp. pretreatment had limited development, reflected in their negative growth rate (−0.6 ± 0.2 mg/d). In conclusion, cultivation of H. illucens larvae (six day old) on BSG pretreated with Pleurotus sp. is not recommended. On the other hand, T. reesei C2A pretreatment enhance BSG reduction, and its potential use for lignocellulosic waste management should be more explored.

Therapeutic Options for the Management of Pompe Disease: Current Challenges and Clinical Evidence in Therapeutics and Clinical Risk Management.

Pompe disease is a genetic disorder produced by mutations in the GAA gene leading to absence or reduced expression of acid alpha-glucosidase, an enzyme that metabolizes the breakdown of glycogen into glucose. There are two main phenotypes, the infantile consisting of early onset severe weakness and cardiomyopathy, and the adult which is characterized by slowly progressive skeletal and respiratory muscle weakness. Enzymatic replacement therapy (ERT) has been available for Pompe disease for more than 15 years. Although the treatment has improved many aspects of the disease, such as prolonged survival through improved cardiomyopathy and acquisition of motor milestones in infants and slower progression rate in adults, ERT is far from being a cure as both infantile and adult patients continue to progress. This fact has prompted the development of improved or new enzymes and other treatments such as gene therapy or substrate reduction strategies. Here, we review the data obtained from randomized clinical trials but also from open-label studies published so far that have assessed the advantages and limitations of this therapy. Moreover, we also review the new therapeutic strategies that are under development and provide our opinion on which are the unmet needs for patients with this disease.

Glucosylsphingosine (Lyso-Gb1): An Informative Biomarker in the Clinical Monitoring of Patients with Gaucher Disease

Historically, disease burden and treatment responses in patients with Gaucher disease (GD) was assessed by monitoring clinical data, laboratory, imaging, chitotriosidase (CHITO), and other biomarkers; however, these biomarkers lack specificity and CHITO is uninformative in patients heterozygous or homozygous for the CHIT1 c.1049_1072dup24 variant. Recently, glucosylsphingosine (lyso-Gb1), a sensitive and specific GD biomarker, has been recommended for patient monitoring. Furthermore, studies measuring lyso-Gb1 and CHITO in patients on long-term treatment with enzyme replacement therapy (ERT) and/or substrate reduction therapy (SRT) reported as group data show a reduction in both analytes, yet individualized patient data are generally unavailable. We describe seven patients on long-term treatment with longitudinal clinical data with monitoring based on current treatment guidelines. We present four patients who exhibit stable disease with normalized CHITO despite elevated lyso-Gb1. We present one patient who transitioned from ERT to SRT due to lack of a clinical response with life-threatening thrombocytopenia who responded with marked improvement in platelets, and normalized levels of both CHITO and lyso-Gb1. Finally, we present two ERT to SRT switch patients with stable disease on ERT who exhibited non-compliance on SRT, one with mirrored marked elevations of CHITO and lyso-Gb1; and another with normal CHITO and platelets, but increasing lyso-Gb1 levels and enlarged spleen. These clinical vignettes highlight the role of lyso-Gb1 as a sensitive biomarker in management of patients with GD, and its further value when CHITO is normal and thus uninformative. We highlight the personalized medicine approach needed to optimize treatment outcomes and recommendations for these patients.