Globotriaosylceramide is correlated with oxidative stress and inflammation in Fabry patients treated with enzyme replacement therapy

Inflammation in Fabry disease: stages, molecular pathways, and therapeutic implications

Fabry disease, a multisystem X-linked disorder caused by mutations in the alpha-galactosidase gene. This leads to the accumulation of globotriaosylceramide (Gb3) and globotriaosylsphingosine (Lyso-Gb3), culminating in various clinical signs and symptoms that significantly impact quality of life. Although treatments such as enzyme replacement, oral chaperone, and emerging therapies like gene therapy exist; delayed diagnosis often curtails their effectiveness. Our review highlights the importance of delineating the stages of inflammation in Fabry disease to enhance the timing and efficacy of diagnosis and interventions, particularly before the progression to fibrosis, where treatment options are less effective. Inflammation is emerging as an important aspect of the pathogenesis of Fabry disease. This is thought to be predominantly mediated by the innate immune response, with growing evidence pointing towards the potential involvement of adaptive immune mechanisms that remain poorly understood. Highlighted by the fact that Fabry disease shares immune profiles with systemic autoinflammatory diseases, blurring the distinctions between these disorders and highlighting the need for a nuanced understanding of immune dynamics. This insight is crucial for developing targeted therapies and improving the administration of current treatments like enzyme replacement. Moreover, our review discusses the complex interplay between these inflammatory processes and current treatments, such as the challenges posed by anti-drug antibodies. These antibodies can attenuate the effectiveness of therapies, necessitating more refined approaches to mitigate their impact. By advancing our understanding of the molecular changes, inflammatory mediators and causative factors that drive inflammation in Fabry disease, we aim to clarify their role in the disease's progression. This improved understanding will help us see how these processes fit into the current landscape of Fabry disease. Additionally, it will guide the development of more effective diagnostic and therapeutic approaches, ultimately improving patient care.

Aseptic meningitis and Fabry disease

OBJECTIVE

Fabry disease is caused by enzymatic defects in alpha-galactosidase A that leads to the accumulation of glycosphingolipids throughout the body, resulting in a multisystemic disorder. The most common neurological manifestations are neuropathic pain, autonomic nervous system dysfunction and strokes, but some rarer neurological manifestations exist. Among these, aseptic meningitis is a possible complication. Our objectives were to measure the prevalence of this complication in a cohort of patients with Fabry disease, and to describe its clinical features.

METHODS

We conducted a retrospective review of Fabry disease patients followed at our tertiary referral center between 1995 and September 2023 with at least one episode of meningitis, and performed a systematic review to identify similar published cases.

RESULTS

Four patients out of 107 (3.7%) had at least one episode of aseptic meningitis. Our systematic review identified 25 other observations. The median age of these 29 patients was 29.0 years, the median cerebrospinal fluid leukocyte count was 24 cells/mm3 with a predominance of lymphocytes in 64.7% of cases. In 82.8% of the patients, the diagnosis of Fabry disease was unknown before the meningitis. Large artery stenosis was present in 17.2% of patients and 57.1% of patients had a recent stroke concomitant with the meningitis. Several differential diagnoses were evoked, such as multiple sclerosis or central nervous system vasculitis.

INTERPRETATION

Our study suggests that Fabry disease should be considered as a cause of aseptic meningitis. The pathophysiological mechanisms underlying meningeal inflammation remain largely unknown but may reflect the dysregulation of pro-inflammatory signaling pathways.

Inflammatory and Cardiovascular Biomarkers to Monitor Fabry Disease Progression

Fabry disease is an invalidating multisystemic disorder affecting α-Galactosidase, a rate-limiting hydrolase dedicated to lipid catabolism. Non-metabolized substrates, such as Globotriaosylceramide and its derivatives trigger the direct or indirect activation of inflammatory events and endothelial dysfunction. In spite of the efficacy demonstrated by enzyme replacement therapy or pharmacological chaperones in delaying disease progression, few studies have analyzed whether these treatments can improve the pro-inflammatory state of FD patients. Therefore, the aim of this work was to assess cytokines and cardiovascular risk-related proteins detectable in plasma from FD patients, whether treated or not with ERT, to evaluate the reliability of these markers in monitoring disease stage and treatment effects. We identified inflammatory and endothelial dysfunction markers (ADAMTS-13, TNF-α, GDF-15, MIP-1β, VEGFA, MPO, and MIC-1) that cooperate in a common pathway and are increased in FD patients' plasma samples. As shown by the assessment of these proteins over time, they can help to evaluate the risk of higher severity in FD, as well as ERT effects. Even though the analyzed proteins cannot be considered as proper biomarkers due to their non-specificity to FD, taken together they can provide a signature of reference molecules with prognostic value for early diagnosis, and evaluation of disease progression and treatment efficacy, using blood samples.

The Effect of Fabry Disease Therapy on Bone Mineral Density

Fabry disease (FD) is an X-linked lysosomal storage disorder, characterised by the cellular accumulation of globotriaosylceramide due to impaired alpha-galactosidase A enzyme activity. FD may manifest with multisystem pathology, including reduced bone mineral density (BMD). Registry data suggest that the introduction of Fabry-specific therapies (enzyme replacement therapy or chaperone therapy) has led to significant improvements in overall patient outcomes; however, there are limited data on the impact on bone density. The aim of this study was to describe the effect of Fabry-specific therapies on longitudinal changes in bone mineral density (BMD) in FD. We performed a retrospective observational study analysing bone densitometry (DXA) in patients with genetically confirmed FD. Patients were grouped based on the use of Fabry-specific therapies. The between-group longitudinal change in BMD Z-score was analysed using linear mixed effects models. A total of 88 FD patients were analysed (50 untreated; 38 treated). The mean age at first DXA was 38.5 years in the untreated group (84% female) and 43.7 years in the treated group (34% female). There was no significant longitudinal between-group difference in the BMD Z-score at the lumbar spine. However, the Z-score per year at the total hip (β = -0.105, p < 0.001) and femoral neck (β = -0.081, p = 0.001) was significantly lower over time in the treated than the untreated group. This may reflect those receiving therapy having a more severe underlying disease. Nevertheless, this suggests that Fabry-specific therapies do not reverse all disease mechanisms and that the additional management of BMD may be required in this patient population.

Mass cytometry reveals atypical immune profile notably impaired maturation of memory CD4 T with Gb3-related CD27 expression in CD4 T cells in Fabry disease

Fabry disease (FD) is an X-linked disease characterized by an accumulation of glycosphingolipids, notably of globotriaosylceramide (Gb3) and globotriaosylsphingosine (lysoGb3) leading to renal failure, cardiomyopathy, and cerebral strokes. Inflammatory processes are involved in the pathophysiology. We investigated the immunological phenotype of peripheral blood mononuclear cells in Fabry patients depending on the clinical phenotype, treatment, Gb3, and lysoGb3 levels and the presence of anti-drug antibodies (ADA). Leucocytes from 41 male patients and 20 controls were analyzed with mass cytometry using both unsupervised and supervised algorithms. FD patients had an increased expression of CD27 and CD28 in memory CD45- and CD45 + CCR7-CD4 T cells (respectively p < 0.014 and p < 0.02). Percentage of CD45RA-CCR7-CD27 + CD28+ cells in CD4 T cells was correlated with plasma lysoGb3 (r = 0.60; p = 0.0036) and phenotype (p < 0.003). The correlation between Gb3 and CD27 in CD4 T cells almost reached significance (r = 0.33; p = 0.058). There was no immune profile associated with the presence of ADA. Treatment with agalsidase beta was associated with an increased proportion of Natural Killer cells. These findings provide valuable insights for understanding FD, linking Gb3 accumulation to inflammation, and proposing new prognostic biomarkers.

The role of tubular cells in the pathogenesis of Fabry nephropathy

The pathophysiology of Fabry nephropathy (FN) is induced by galactosidase A deficiency with a chronic exposure of glycolipids to every lineage of renal cells. Tissue damage is attributed to the activation of molecular pathways, resulting in tissue fibrosis and chronic kidney disease. Podocytes have been the primary focus in clinical pathophysiological research because of the striking accumulation of large glycolipid deposits observable in histology. Yet, the tubular interstitium makes up a large portion of the whole organ, and therefore, its role must be further considered in pathogenic processes. In this review, we would like to propose Fabry tubulopathy and its ensuing functional effects as the first pathological signs and contributing factors to the development of FN. We will summarize and discuss the current literature regarding the role of tubular cells in Fabry kidney pathophysiology. Starting from clinical and histological evidence, we will highlight the data from animal models and cell cultures outlining the pathophysiological pathways associated with tubular interstitial injury causing renal fibrosis in Fabry nephropathy.

A Systematic Review on Safety and Efficacy of Migalastat for the treatment of Fabry's Disease

INTRODUCTION

Fabry's disease (FD) is a genetic lysosomal storage disorder characterized by α-galactosidase A (α-Gal A) lost/reduced activity. We aim to systematically assess the safety and efficacy of Migalastat, an oral pharmacological chaperone, that has been approved for the treatment of FD in patients with amenable mutations.

METHODS

We conducted literature search following the PRISMA guidelines in major databases up to 4 February 2024, for studies that assessed the clinical outcomes of migalastat in patients with FD. The New Castle Ottawa Scale was used to evaluate the quality of the included studies.

RESULTS

A total of 2141 records were identified through database searches and register searches, amongst which 26 records were screened, and 12 of these were excluded. The remaining 14 reports were sought for retrieval. The 12 retrieved articles were assessed for eligibility and their quality was assessed after their inclusion. Amongst the included studies, 5 were of high quality, 6 were of medium quality, and 1 was of low quality.

CONCLUSION

Migalastat showed varied effects on enzyme activity and substrate levels, with gender-specific differences noted in GL-3 substrate activity and eGFR. Overall, it improved cardiac and renal outcomes similarly to enzyme replacement therapy, with a comparable safety profile.

Fabry Disease: Cardiac Implications and Molecular Mechanisms

PURPOSE OF REVIEW

This review explores the interplay among metabolic dysfunction, oxidative stress, inflammation, and fibrosis in Fabry disease, focusing on their potential implications for cardiac involvement. We aim to discuss the biochemical processes that operate in parallel to sphingolipid accumulation and contribute to disease pathogenesis, emphasizing the importance of a comprehensive understanding of these processes.

RECENT FINDINGS

Beyond sphingolipid accumulation, emerging studies have revealed that mitochondrial dysfunction, oxidative stress, and chronic inflammation could be significant contributors to Fabry disease and cardiac involvement. These factors promote cardiac remodeling and fibrosis and may predispose Fabry patients to conduction disturbances, ventricular arrhythmias, and heart failure. While current treatments, such as enzyme replacement therapy and pharmacological chaperones, address disease progression and symptoms, their effectiveness is limited. Our review uncovers the potential relationships among metabolic disturbances, oxidative stress, inflammation, and fibrosis in Fabry disease-related cardiac complications. Current findings suggest that beyond sphingolipid accumulation, other mechanisms may significantly contribute to disease pathogenesis. This prompts the exploration of innovative therapeutic strategies and underscores the importance of a holistic approach to understanding and managing Fabry disease.

Infertility in Fabry's Disease: role of hypoxia and inflammation in determining testicular damage

Introduction

Fabry's disease (FD) is a genetic X-linked systemic and progressive rare disease characterized by the accumulation of globotriaosylceramide (GB3) into the lysosomes of many tissues. FD is due to loss-of-function mutations of α-galactosidase, a key-enzyme for lysosomal catabolism of glycosphingolipids, which accumulate as glycolipid bodies (GB). In homozygous males the progressive deposition of GB3 into the cells leads to clinical symptoms in CNS, skin, kidney, etc. In testis GB accumulation causes infertility and alterations of spermatogenesis. However, the precise damaging mechanism is still unknown. Our hypothesis is that GB accumulation reduces blood vessel lumen and increases the distance of vessels from both stromal cells and seminiferous parenchyma; this, in turn, impairs oxygen and nutrients diffusion leading to subcellular degradation of seminiferous epithelium and sterility.

Methods

To test this hypothesis, we have studied a 42-year-old patient presenting a severe FD and infertility, with reduced number of spermatozoa, but preserved sexual activity. Testicular biopsies were analyzed by optical (OM) and transmission electron microscopy (TEM). Activation and cellular localization of HIF-1α and NFκB was analyzed by immunofluorescence (IF) and RT-PCR on homogeneous tissue fractions after laser capture microdissection (LCMD).

Results

OM and TEM showed that GB were abundant in vessel wall cells and in interstitial cells. By contrast, GB were absent in seminiferous epithelium, Sertoli's and Leydig's cells. However, seminiferous tubular epithelium and Sertoli's cells showed reduced diameter, thickening of basement membrane and tunica propria, and swollen or degenerated spermatogonia. IF showed an accumulation of HIF-1α in stromal cells but not in seminiferous tubules. On the contrary, NFκB fluorescence was evident in tubules, but very low in interstitial cells. Finally, RT-PCR analysis on LCMD fractions showed the expression of pro-inflammatory genes connected to the HIF-1α/NFκB inflammatory-like pathway.

Conclusion

Our study demonstrates that infertility in FD may be caused by reduced oxygen and nutrients due to GB accumulation in blood vessels cells. Reduced oxygen and nutrients alter HIF-1α/NFκB expression and localization while activating HIF-1α/NFκB driven-inflammation-like response damaging seminiferous tubular epithelium and Sertoli's cells.

Increased Soluble Interleukin 6 Receptors in Fabry Disease

Fabry disease (FD) is an X-linked lysosome storage disease that results in the accumulation of globotriaosylceramide (Gb3) throughout the body leading to irreversible target organ damage. As the role of secondary mediators (inflammatory molecules) and their mechanisms has not been fully elucidated, we focused on the interleukin (IL)-6 system in adult FD patients and in matched healthy subjects. To obtain insights into the complex regulation of IL-6 actions, we used a novel approach that integrates information from plasma and exosomes of FD patients (n = 20) and of healthy controls (n = 15). Soluble IL-6 receptor (sIL-6R) levels were measured in plasma with the ELISA method, and membrane-bound IL-6R was quantified in plasma and urinary exosomes using flow cytometry. In FD patients, the levels of soluble IL-6R in plasma were higher than in control subjects (28.0 ± 5.4 ng/mL vs. 18.9 ± 5.4 ng/mL, p < 0.0001); they were also higher in FD subjects with the classical form as compared to those with the late-onset form of the disease (36.0 ± 11.4 ng/mL vs. 26.1 ± 4.5 ng/mL, p < 0.0001). The percentage of urinary exosomes positive for IL-6R was slightly lower in FD (97 ± 1 vs. 100 ± 0% of events positive for IL-6R, p < 0.05); plasma IL-6 levels were not increased. These results suggest a potential role of IL-6 in triggering the inflammatory response in FD. As in FD patients only the levels of sIL-6Rs are consistently higher than in healthy controls, the IL-6 pathogenic signal seems to prevail over the homeostatic one, suggesting a potential mechanism causing multi-systemic damage in FD.

Thiol/disulfide homeostasis as a new oxidative stress marker in patients with Fabry disease

This is the first study to show both dynamic thiol-disulfide balance and oxidative stress levels in patients with Fabry disease (FD). This prospective study consists of 30 FD patients and 30 healthy controls. Thiol and disulfide values of the study groups were evaluated using a new, cost-effective and fully automatic colorimetric method. A total of 60 subjects were included in the study. A statistically significant difference was found between the patient and control groups for native and total thiol levels (p < 0.001). In addition, disulfide levels were significantly higher in FD patients compared with the control group (p < 0.003). Native thiol levels showed significantly negative correlation with lysosomal globotriaosylceramide, total oxidant status (TOS), and oxidative stress index (OSI) levels. In addition, a positive correlation was found between disulfide/natural thiol and disulfide/total thiol ratios and TOS, OSI, and blood urea nitrogen. We found total antioxidant status levels were lower in the patient group compared to the control group, while TOS and OSI levels were higher and were statistically significant. This study highlights for the first time a novel, cost-effective and fully automated measurement of thiol-disulfide levels in patients with FD. Determination of thiol levels can make important contributions to understand the etiopathogenesis and follow-up of the disease in FD patients.

Relief of nocturnal neuropathic pain with the use of cannabis in a patient with Fabry disease

Neuropathic pain is one of the most invalidating symptoms in patients with Fabry disease (FD), affecting their quality of life, it is linked to small fiber neuropathy and it may not respond to available disease specific treatments. We report the case of a 32 years old man with classic FD and severe neuropathic pain who, after the failure of several standard pharmaceutical approaches, was treated with medical cannabis with relief of nocturnal pain and sleep improvement.

Endothelial Cell Dysfunction and Hypoxia as Potential Mediators of Pain in Fabry Disease: A Human-Murine Translational Approach

Fabry disease (FD) is caused by α-galactosidase A (AGAL) enzyme deficiency, leading to globotriaosylceramide accumulation (Gb3) in several cell types. Pain is one of the pathophysiologically incompletely understood symptoms in FD patients. Previous data suggest an involvement of hypoxia and mitochondriopathy in FD pain development at dorsal root ganglion (DRG) level. Using immunofluorescence and quantitative real-time polymerase chain reaction (qRT PCR), we investigated patient-derived endothelial cells (EC) and DRG tissue of the GLA knockout (KO) mouse model of FD. We address the question of whether hypoxia and mitochondriopathy contribute to FD pain pathophysiology. In EC of FD patients (P1 with pain and, P2 without pain), we found dysregulated protein expression of hypoxia-inducible factors (HIF) 1a and HIF2 compared to the control EC (p < 0.01). The protein expression of the HIF downstream target vascular endothelial growth factor A (VEGFA, p < 0.01) was reduced and tube formation was hampered in the P1 EC compared to the healthy EC (p < 0.05). Tube formation ability was rescued by applying transforming growth factor beta (TGFβ) inhibitor SB-431542. Additionally, we found dysregulated mitochondrial fusion/fission characteristics in the P1 and P2 EC (p < 0.01) and depolarized mitochondrial membrane potential in P2 compared to control EC (p < 0.05). Complementary to human data, we found upregulated hypoxia-associated genes in the DRG of old GLA KO mice compared to WT DRG (p < 0.01). At protein level, nuclear HIF1a was higher in the DRG neurons of old GLA KO mice compared to WT mice (p < 0.01). Further, the HIF1a downstream target CA9 was upregulated in the DRG of old GLA KO mice compared to WT DRG (p < 0.01). Similar to human EC, we found a reduction in the vascular characteristics in GLA KO DRG compared to WT (p < 0.05). We demonstrate increased hypoxia, impaired vascular properties, and mitochondrial dysfunction in human FD EC and complementarily at the GLA KO mouse DRG level. Our data support the hypothesis that hypoxia and mitochondriopathy in FD EC and GLA KO DRG may contribute to FD pain development.

Proteomic analysis unveils Gb3-independent alterations and mitochondrial dysfunction in a gla-/- zebrafish model of Fabry disease

BACKGROUND

Fabry disease (FD) is a rare lysosomal storage disorder caused by mutations in the GLA gene, resulting in reduced or lack of α-galactosidase A activity. This results in the accumulation of globotriaosylceramide (Gb3) and other glycosphingolipids in lysosomes causing cellular impairment and organ failures. While current therapies focus on reversing Gb3 accumulation, they do not address the altered cellular signaling in FD. Therefore, this study aims to explore Gb3-independent mechanisms of kidney damage in Fabry disease and identify potential biomarkers.

METHODS

To investigate these mechanisms, we utilized a zebrafish (ZF) gla-/- mutant (MU) model. ZF naturally lack A4GALT gene and, therefore, cannot synthesize Gb3. We obtained kidney samples from both wild-type (WT) (n = 8) and MU (n = 8) ZF and conducted proteome profiling using untargeted mass spectrometry. Additionally, we examined mitochondria morphology and cristae morphology using electron microscopy. To assess oxidative stress, we measured total antioxidant activity. Finally, immunohistochemistry was conducted on kidney samples to validate specific proteins.

RESULTS

Our proteomics analysis of renal tissues from zebrafish revealed downregulation of lysosome and mitochondrial-related proteins in gla-/- MU renal tissues, while energy-related pathways including carbon, glycolysis, and galactose metabolisms were disturbed. Moreover, we observed abnormal mitochondrial shape, disrupted cristae morphology, altered mitochondrial volume and lower antioxidant activity in gla-/- MU ZF.

CONCLUSIONS

These results suggest that the alterations observed at the proteome and mitochondrial level closely resemble well-known GLA mutation-related alterations in humans. Importantly, they also unveil novel Gb3-independent pathogenic mechanisms in Fabry disease. Understanding these mechanisms could potentially lead to the development of innovative drug screening approaches. Furthermore, the findings pave the way for identifying new clinical targets, offering new avenues for therapeutic interventions in Fabry disease. The zebrafish gla-/- mutant model proves valuable in elucidating these mechanisms and may contribute significantly to advancing our knowledge of this disorder.

Evaluation of biochemical profile and oxidative damage to lipids and proteins in patients with lysosomal acid lipase deficiency

Lysosomal acid lipase deficiency (LALD) is an inborn error of metabolism that lacks satisfactory treatment, which leads to the development of severe hepatic and cardiac complications and may even lead to death. In this sense, knowledge of the mechanisms involved in the pathophysiology of this disorder becomes essential to allow the search for new therapeutic strategies. There are no studies in the literature investigating the role of reactive species and inflammatory processes in the pathophysiology of this disorder. Therefore, the aim of this work was to investigate parameters of oxidative and inflammatory stress in LALD patients. In this work, we obtained results that demonstrate that LALD patients are susceptible to oxidative stress caused by an increase in the production of free radicals, observed by the increase of 2-7-dihydrodichlorofluorescein. The decrease in sulfhydryl content reflects oxidative damage to proteins, as well as a decrease in antioxidant defenses. Likewise, the increase in urinary levels of di-tyrosine observed also demonstrates oxidative damage to proteins. Furthermore, the determination of chitotriosidase activity in the plasma of patients with LALD was significantly higher, suggesting a pro-inflammatory state. An increase in plasma oxysterol levels was observed in patients with LALD, indicating an important relationship between this disease and cholesterol metabolism and oxidative stress. Also, we observed in LALD patients increased levels of nitrate production. The positive correlation found between oxysterol levels and activity of chitotriosidase in these patients indicates a possible link between the production of reactive species and inflammation. In addition, an increase in lipid profile biomarkers such as total and low-density lipoprotein cholesterol were demonstrated in the patients, which reinforces the involvement of cholesterol metabolism. Thus, we can assume that, in LALD, oxidative and nitrosative damage, in addition to inflammatory process, play an important role in its evolution and future clinical manifestations. In this way, we can suggest that the study of the potential benefit of the use of antioxidant and anti-inflammatory substances as an adjuvant tool in the treatment will be important, which should be associated with the already recommended therapy.

Circulating Anti-GB3 Antibody as a Biomarker of Myocardial Inflammation in Patients with Fabry Disease Cardiomyopathy

BACKGROUND

Fabry disease cardiomyopathy (FDCM) has manifested some resistance to enzyme replacement therapy (ERT), particularly in its advanced phase. Recently, myocardial inflammation of autoimmune origin has been demonstrated in FDCM.

AIMS

The objective of this study was the assessment of circulating anti-globotriaosylceramide (GB3) antibodies as potential biomarkers of myocardial inflammation in FDCM, defined by the additional presence of ≥CD3+ 7 T lymphocytes/low-power field associated with focal necrosis of adjacent myocytes. Its sensitivity was based on the evidence of overlapping myocarditis at left ventricular endomyocardial biopsy.

METHODS AND RESULTS

From January 1996 to December 2021, 85 patients received a histological diagnosis of FDCM in our department and 48 (56.5%) of them had an overlapping myocardial inflammation with negative PCR for common cardiotropic viruses, positive antiheart, and antimyosin abs. The presence of anti-GB3 antibodies was evaluated with an in-house ELISA assay (BioGeM scarl Medical Investigational Research, MIR-Ariano Irpino, Italy), along with antiheart and antimyosin abs, in the FDCM patients and compared with control healthy individuals. The correlation between levels of circulating anti-GB3 autoantibody myocardial inflammation and FDCM severity was assessed. Anti-Gb3 antibodies were above the positivity cut-off in 87.5% of FDCM subjects with myocarditis (42 out of 48), while 81.1% of FDCM patients without myocarditis were identified as negative for Gb3 antibodies. Positive anti-Gb3 abs correlated with positive antiheart and antimyosin abs.

CONCLUSIONS

The present study suggests a potential positive role of anti-GB3 antibodies as a marker of overlapping cardiac inflammation in patients with FDCM.

Endocrinological, immunological and metabolic features of patients with Fabry disease under therapy

OBJECTIVES

Fabry disease is an X-linked lysosomal disorder caused by decreased or absent alpha galactosidase enzyme. The enzyme deficiency leads to progressive accumulation of globotriaosylceramide (Gb-3) and its deacetylated form lyso-Gb3 in various tissue lysosomes that results in primarily lysosomal deterioration and subsequently mitochondrial, endothelial, and immunologic dysfunctions.

METHODS

The endocrinological, metabolic, immunological and HLA status of 12 patients were evaluated.

RESULTS

A total of 11 patients (91.6 %) had immunologic and/or endocrinologic abnormalities. fT4, anti-TPO, and anti-TG levels were increased in 1, 2, and 2 patients, respectively. Three patients had elevated proinflammatory cytokines. ANA profile, p-ANCA and c-ANCA were positive in 1, 1, and 2 patients, respectively. Tissue transglutaminase antibody was negative in all patients however P5 was diagnosed with Celiac disease at the age of 12 and on gluten free diet. All patients had distinct types of HLA apart from 2 patients with anti-TG and anti-TPO positive and there was no relationship between the HLA types and the autoimmunity biomarkers.

CONCLUSIONS

FD may have impact on endocrinologic and immunologic abnormalities even in the patients under ERT, therefore prevalence of these abnormalities may be higher in ERT naïve patients. However, apparently, they are less likely to cause clinical symptoms. Certain HLA alleles may contribute to the direct impact of immunological pathogenesis in FD by developing abnormal autoimmune biomarkers. To the best of our knowledge, this is the first study investigating HLA status of FD patients; therefore further studies are needed to elucidate the underlying mechanism of action.

Inflammation across the spectrum of hypertrophic cardiac phenotypes

The hypertrophic cardiomyopathy phenotype encompasses a heterogeneous spectrum of genetic and acquired diseases characterized by the presence of left ventricular hypertrophy in the absence of abnormal cardiac loading conditions. This "umbrella diagnosis" includes the "classic" hypertrophic cardiomyopathy (HCM), due to sarcomere protein gene mutations, and its phenocopies caused by intra- or extracellular deposits, such as Fabry disease (FD) and cardiac amyloidosis (CA). All these conditions share a wide phenotypic variability which results from the combination of genetic and environmental factors and whose pathogenic mediators are poorly understood so far. Accumulating evidence suggests that inflammation plays a critical role in a broad spectrum of cardiovascular conditions, including cardiomyopathies. Indeed, inflammation can trigger molecular pathways which contribute to cardiomyocyte hypertrophy and dysfunction, extracellular matrix accumulation, and microvascular dysfunction. Growing evidence suggests that systemic inflammation is a possible key pathophysiologic process potentially involved in the pathogenesis of cardiac disease progression, influencing the severity of the phenotype and clinical outcome, including heart failure. In this review, we summarize current knowledge regarding the prevalence, clinical significance, and potential therapeutic implications of inflammation in HCM and two of its most important phenocopies, FD and CA.

Exploring Pro-Inflammatory Immunological Mediators: Unraveling the Mechanisms of Neuroinflammation in Lysosomal Storage Diseases

Lysosomal storage diseases are a group of rare and ultra-rare genetic disorders caused by defects in specific genes that result in the accumulation of toxic substances in the lysosome. This excess accumulation of such cellular materials stimulates the activation of immune and neurological cells, leading to neuroinflammation and neurodegeneration in the central and peripheral nervous systems. Examples of lysosomal storage diseases include Gaucher, Fabry, Tay–Sachs, Sandhoff, and Wolman diseases. These diseases are characterized by the accumulation of various substrates, such as glucosylceramide, globotriaosylceramide, ganglioside GM2, sphingomyelin, ceramide, and triglycerides, in the affected cells. The resulting pro-inflammatory environment leads to the generation of pro-inflammatory cytokines, chemokines, growth factors, and several components of complement cascades, which contribute to the progressive neurodegeneration seen in these diseases. In this study, we provide an overview of the genetic defects associated with lysosomal storage diseases and their impact on the induction of neuro-immune inflammation. By understanding the underlying mechanisms behind these diseases, we aim to provide new insights into potential biomarkers and therapeutic targets for monitoring and managing the severity of these diseases. In conclusion, lysosomal storage diseases present a complex challenge for patients and clinicians, but this study offers a comprehensive overview of the impact of these diseases on the central and peripheral nervous systems and provides a foundation for further research into potential treatments.

Biochemical Mechanisms beyond Glycosphingolipid Accumulation in Fabry Disease: Might They Provide Additional Therapeutic Treatments?

Fabry disease is a rare X-linked disease characterized by deficient expression and activity of alpha-galactosidase A (α-GalA) with consequent lysosomal accumulation of glycosphingolipid in various organs. Currently, enzyme replacement therapy is the cornerstone of the treatment of all Fabry patients, although in the long-term it fails to completely halt the disease's progression. This suggests on one hand that the adverse outcomes cannot be justified only by the lysosomal accumulation of glycosphingolipids and on the other that additional therapies targeted at specific secondary mechanisms might contribute to halt the progression of cardiac, cerebrovascular, and renal disease that occur in Fabry patients. Several studies reported how secondary biochemical processes beyond Gb3 and lyso-Gb3 accumulation-such as oxidative stress, compromised energy metabolism, altered membrane lipid, disturbed cellular trafficking, and impaired autophagy-might exacerbate Fabry disease adverse outcomes. This review aims to summarize the current knowledge of these pathogenetic intracellular mechanisms in Fabry disease, which might suggest novel additional strategies for its treatment.

Aseptic meningitis in Fabry disease due to a novel GLA variant: an expanded phenotype?

BACKGROUND

F abry disease (FD) is an X-linked lysosomal storage disorder with accumulation of globotriosylceramide, causing neurologic involvement mainly as acroparesthesias and cerebrovascular disease. Aseptic meningitis has been reported in 11 patients with FD, but no prior study has correlated alpha-galactosidase (GLA) specific variants with meningitis. We present in this manuscript a family in which a novel GLA pathogenic variant was associated with aseptic meningitis in 2 of 5 family members.

METHODS

This study began with identifying the proband, then screening family members for FD symptoms and evaluating symptomatic individuals for genetic and biochemical status. All patients underwent magnetic resonance imaging, and those with headache underwent cerebrospinal fluid (CSF) analysis.

RESULTS

Five patients (3 females) from a single family were included in this study. Mean age at diagnosis was 20.6 years. Two patients (40%) had aseptic meningitis; one of them also had cerebrovascular events. C-reactive protein and erythrocyte sedimentation rate were elevated during aseptic meningitis episodes. Both patients responded to intravenous methylprednisolone with resolution of fever, headache, and vomiting. One of them recurred and needed chronic immunosuppression with azathioprine.

CONCLUSION

We described aseptic meningitis in a family with a novel GLA variant. Meningitis might be a common phenomenon in FD and not a particularity of this variant. Understanding the mechanisms underlying meningitis and its association with cerebrovascular events may lead to a new paradigm of treatment for stroke in these patients. Further prospective studies with CSF collection in patients with FD and recurrent headache could help to elucidate this question.

Gene Expression Analysis in gla-Mutant Zebrafish Reveals Enhanced Ca2+ Signaling Similar to Fabry Disease

Fabry disease (FD) is an X-linked inborn metabolic disorder due to partial or complete lysosomal α-galactosidase A deficiency. FD is characterized by progressive renal insufficiency and cardio- and cerebrovascular involvement. Restricted access on Gb3-independent tissue injury experimental models has limited the understanding of FD pathophysiology and delayed the development of new therapies. Accumulating glycosphingolipids, mainly Gb3 and lysoGb3, are Fabry specific markers used in clinical follow up. However, recent studies suggest there is a need for additional markers to monitor FD clinical course or response to treatment. We used a gla-knockout zebrafish (ZF) to investigate alternative biomarkers in Gb3-free-conditions. RNA sequencing was used to identify transcriptomic signatures in kidney tissues discriminating gla-mutant (M) from wild type (WT) ZF. Gene Ontology (GO) and KEGG pathways analysis showed upregulation of immune system activation and downregulation of oxidative phosphorylation pathways in kidneys from M ZF. In addition, upregulation of the Ca²⁺ signaling pathway was also detectable in M ZF kidneys. Importantly, disruption of mitochondrial and lysosome-related pathways observed in M ZF was validated by immunohistochemistry. Thus, this ZF model expands the pathophysiological understanding of FD, the Gb3-independent effects of gla mutations could be used to explore new therapeutic targets for FD.

Fabry disease: Mechanism and therapeutics strategies

Fabry disease is a monogenic disease characterized by a deficiency or loss of the α-galactosidase A (GLA). The resulting impairment in lysosomal GLA enzymatic activity leads to the pathogenic accumulation of enzymatic substrate and, consequently, the progressive appearance of clinical symptoms in target organs, including the heart, kidney, and brain. However, the mechanisms involved in Fabry disease-mediated organ damage are largely ambiguous and poorly understood, which hinders the development of therapeutic strategies for the treatment of this disorder. Although currently available clinical approaches have shown some efficiency in the treatment of Fabry disease, they all exhibit limitations that need to be overcome. In this review, we first introduce current mechanistic knowledge of Fabry disease and discuss potential therapeutic strategies for its treatment. We then systemically summarize and discuss advances in research on therapeutic approaches, including enzyme replacement therapy (ERT), gene therapy, and chaperone therapy, as well as strategies targeting subcellular compartments, such as lysosomes, the endoplasmic reticulum, and the nucleus. Finally, the future development of potential therapeutic strategies is discussed based on the results of mechanistic studies and the limitations associated with these therapeutic approaches.

Prediction of Regulatory SNPs in Putative Minor Genes of the Neuro-Cardiovascular Variant in Fabry Reveals Insights into Autophagy/Apoptosis and Fibrosis

Even though a mutation in monogenic diseases leads to a “classic” manifestation, many disorders exhibit great clinical variability that could be due to modifying genes also called minor genes. Fabry disease (FD) is an X-linked inborn error resulting from the deficient or absent activity of alpha-galactosidase A (α-GAL) enzyme, that leads to deposits of globotriaosylceramide. With our proprietary software SNPclinic v.1.0, we analyzed 110 single nucleotide polymorphisms (SNPs) in the proximal promoter of 14 genes that could modify the FD phenotype FD. We found seven regulatory-SNP (rSNPs) in three genes (IL10, TGFB1 and EDN1) in five cell lines relevant to FD (Cardiac myocytes and fibroblasts, Astrocytes-cerebellar, endothelial cells and T helper cells 1-TH1). Each SNP was confirmed as a true rSNP in public eQTL databases, and additional software suggested the prediction of variants. The two proposed rSNPs in IL10, could explain components for the regulation of active B cells that influence the fibrosis process. The three predicted rSNPs in TGFB1, could act in apoptosis-autophagy regulation. The two putative rSNPs in EDN1, putatively regulate chronic inflammation. The seven rSNPs described here could act to modulate Fabry’s clinical phenotype so we propose that IL10, TGFB1 and EDN1 be considered minor genes in FD.

The Effect of Green Tea as an Adjuvant to Enzyme Replacement Therapy on Oxidative Stress in Fabry Disease: A Pilot Study

Enzymatic replacement therapy (ERT) is not very effective in halting the progression of Fabry disease (FD) toward cardiovascular (CV)-renal remodeling, particularly in case of late diagnosis. FD patients have increased oxidative stress (OS), critical for the induction of CV-renal remodeling. We investigated the effects of an adjuvant antioxidant treatment to ERT on OS and the possible advantages for related complications. OS was evaluated in 10 patients with FD before ERT, after 12 months of ERT, and after 6 months of adjuvant green tea (GT) to ERT by the following experiments: expression of p22^phox; phosphorylation state of MYPT-1 and ERK 1/2 (by western blotting); and quantification of malondialdehyde (MDA) and heme oxygenase (HO)-1 levels (by ELISA). p22^phox and MYPT-1 phosphorylation decreased after ERT and significantly further decreased after GT. ERK 1/2 phosphorylation and MDA levels remained unchanged after ERT, but significantly decreased after GT. HO-1 significantly increased after ERT and further increased after GT. This study provides preliminary data highlighting the antioxidant effect exerted by ERT itself, further amplified by the adjuvant antioxidant treatment with GT. The results of this study provide evidence of the positive effect of early additive antioxidant treatment to reduce OS and prevent/alleviate cardio and cerebrovascular-renal complications related to OS.

Inhibition of epigenetic reader proteins by apabetalone counters inflammation in activated innate immune cells from Fabry disease patients receiving enzyme replacement therapy

Fabry disease (FD) is a rare X‐linked disorder of lipid metabolism, characterized by the accumulation of globotriaosylceramide (Gb3) due to defective the lysosomal enzyme, α‐galactosidase. Gb3 deposits activate immune‐mediated systemic inflammation, ultimately leading to life‐threatening consequences in multiple organs such as the heart and kidneys. Enzyme replacement therapy (ERT), the standard of care, is less effective with advanced tissue injury and inflammation in patients with FD. Here, we showed that MCP‐1 and TNF‐α cytokine levels were almost doubled in plasma from ERT‐treated FD patients. Chemokine receptor CCR2 surface expression was increased by twofold on monocytes from patients with low eGFR. We also observed an increase in IL12B transcripts in unstimulated peripheral blood mononuclear cells (PBMCs) over a 2‐year period of continuous ERT. Apabetalone is a clinical‐stage oral bromodomain and extra terminal protein inhibitor (BETi), which has beneficial effects on cardiovascular and kidney disease related pathways including inflammation. Here, we demonstrate that apabetalone, a BD2‐selective BETi, dose dependently reduced the production of MCP‐1 and IL‐12 in stimulated PBMCs through transcriptional regulation of their encoding genes. Reactive oxygen species production was diminished by up to 80% in stimulated neutrophils following apabetalone treatment, corresponding with inhibition of NOX2 transcription. This study elucidates that inhibition of BET proteins by BD2‐selective apabetalone alleviates inflammatory processes and oxidative stress in innate immune cells in general and in FD. These results suggest potential benefit of BD2‐selective apabetalone in controlling inflammation and oxidative stress in FD, which will be further investigated in clinical trials.

CARS Imaging Advances Early Diagnosis of Cardiac Manifestation of Fabry Disease

Vibrational spectroscopy can detect characteristic biomolecular signatures and thus has the potential to support diagnostics. Fabry disease (FD) is a lipid disorder disease that leads to accumulations of globotriaosylceramide in different organs, including the heart, which is particularly critical for the patient’s prognosis. Effective treatment options are available if initiated at early disease stages, but many patients are late- or under-diagnosed. Since Coherent anti-Stokes Raman (CARS) imaging has a high sensitivity for lipid/protein shifts, we applied CARS as a diagnostic tool to assess cardiac FD manifestation in an FD mouse model. CARS measurements combined with multivariate data analysis, including image preprocessing followed by image clustering and data-driven modeling, allowed for differentiation between FD and control groups. Indeed, CARS identified shifts of lipid/protein content between the two groups in cardiac tissue visually and by subsequent automated bioinformatic discrimination with a mean sensitivity of 90–96%. Of note, this genotype differentiation was successful at a very early time point during disease development when only kidneys are visibly affected by globotriaosylceramide depositions. Altogether, the sensitivity of CARS combined with multivariate analysis allows reliable diagnostic support of early FD organ manifestation and may thus improve diagnosis, prognosis, and possibly therapeutic monitoring of FD.

Cytokine profile and cholesterol levels in patients with Niemann-Pick type C disease presenting neurological symptoms: The in vivo effect of miglustat and the in vitro effect of N-acetylcysteine and Coenzyme Q10

Niemann Pick type C is an inborn error of metabolism (IEM), classified as a lysosomal storage disease (LSD) caused by a dysfunction in NPC transport protein, that leads to intracellular accumulation of non-esterified cholesterol and other lipids. Clinical manifestations are ample, with visceral and neurological symptoms. Miglustat, a molecule that reversibly inhibits glucosylceramide synthase is used as treatment for this disorder. Studies demonstrated the influence of oxidative stress and inflammation in IEM, as well in animal model of NP-C disease. Nonetheless, literature lacks data on patients, so our work aimed to investigate if there is influence of chronic inflammation in the pathophysiology of NP-C disease, and the effect of miglustat, N-acetylcysteine (NAC) and Coenzyme Q10 (CoQ10). We evaluated the plasmatic cytokines in NPC patients at diagnosis and during the treatment with miglustat. Additionally, we performed an in vitro study with antioxidants NAC (1 mM and 2.5 mM) and CoQ10 (5 μM and 10 μM), where we could verify its effect on inflammatory parameters, as well as in cholesterol accumulation. Our results showed that NP-C patients have higher plasmatic levels of pro and anti-inflammatory cytokines (IL-6, IL-8, and IL-10) at diagnosis and the treatment with miglustat was able to restore it. In vitro study showed that treatment with antioxidants in higher concentrations significantly decrease cholesterol accumulation, and NAC at 2.5 mM normalized the level of pro-inflammatory cytokines. Although the mechanism is not completely clear, it can be related to restoration in lipid traffic and decrease in oxidative stress caused by antioxidants.

Human kidney organoids reveal the role of glutathione in Fabry disease

Fabry disease is an X-linked lysosomal storage disease caused by a mutation in the galactosidase alpha (GLA) gene. Despite advances in therapeutic technologies, the lack of humanized experimental models of Fabry disease has limited the development of new therapies to cure the disease. Herein, we modeled Fabry disease using human inducible pluripotent stem cell (iPSC)-derived kidney organoids and the CRISPR-Cas9 genome-editing system. GLA-mutant human kidney organoids revealed deformed podocytes and tubular cells with accumulation of globotriaosylceramide (Gb3). Ultrastructural analysis showed abundant electron-dense granular deposits and electron-dense lamellate lipid-like deposits that formed concentric bodies (zebra bodies) in the cytoplasm of podocytes and tubules. The oxidative stress level was increased in GLA-mutant kidney organoids, and the increase was accompanied by apoptosis. Enzyme replacement treatment (ERT) with recombinant human α-Gal A decreased the Gb3 accumulation and oxidative stress, which resulted in amelioration of the deformed cellular structure of the GLA-mutant kidney organoids. Transcription profile analyses showed decreased glutathione (GSH) metabolism in GLA-mutant kidney organoids. GSH replacement treatment decreased oxidative stress and attenuated the structural deformity of the GLA-mutant kidney organoids. GSH treatment also increased the expression of podocyte and tubular markers and decreased apoptosis. In conclusion, GLA-mutant kidney organoids derived from human iPSCs are valuable tools for studying the mechanisms and developing novel therapeutic alternatives for Fabry disease.

Review of Mechanisms, Pharmacological Management, Psychosocial Implications, and Holistic Treatment of Pain in Fabry Disease

Fabry disease is a progressive X-linked lysosomal storage disease caused by a mutation in the GLA gene, encoding the lysosomal hydrolase α-galactosidase A. The consequent reduced enzyme activity results in the toxic accumulation of glycosphingolipids, particularly globortriaosylceramide (Gb3 or GL3), in blood vessels, renal epithelia, myocardium, peripheral nervous system, cornea and skin. Neuropathic pain is the most common manifestation of Fabry disease and can be extremely debilitating. This often develops during childhood and presents with episodes of burning and sharp pain in the hands and feet, especially during exercise and it is worse with increased heat or fever. It is thought to be due to ischaemic injury and metabolic failure, leading to the disruption of neuronal membranes and small fibre neuropathy, caused by a reduced density of myelinated Aδ and unmyelinated C-fibres and alterations in the function of ion channels, mediated by Gb3 and lyso Gb3. It is important to confirm small fibre neuropathy before any Fabry disease treatment modality is considered. There is a clinical need for novel techniques for assessing small fibre function to improve detection of small fibre neuropathy and expand the role of available therapies. The current Fabry disease guidelines are in favour of pharmacological management as the first-line treatment for pain associated with Fabry disease. Refractory cases would benefit from a rehabilitation approach with interdisciplinary input, including medical, physiotherapy and psychological disciplines and including a Pain Management Programme.

Parsing Fabry Disease Metabolic Plasticity Using Metabolomics

Background: Fabry disease (FD) is an X-linked lysosomal disease due to a deficiency in the activity of the lysosomal α-galactosidase A (GalA), a key enzyme in the glycosphingolipid degradation pathway. FD is a complex disease with a poor genotype–phenotype correlation. FD could involve kidney, heart or central nervous system impairment that significantly decreases life expectancy. The advent of omics technologies offers the possibility of a global, integrated and systemic approach well-suited for the exploration of this complex disease. Materials and Methods: Sixty-six plasmas of FD patients from the French Fabry cohort (FFABRY) and 60 control plasmas were analyzed using liquid chromatography and mass spectrometry-based targeted metabolomics (188 metabolites) along with the determination of LysoGb3 concentration and GalA enzymatic activity. Conventional univariate analyses as well as systems biology and machine learning methods were used. Results: The analysis allowed for the identification of discriminating metabolic profiles that unambiguously separate FD patients from control subjects. The analysis identified 86 metabolites that are differentially expressed, including 62 Glycerophospholipids, 8 Acylcarnitines, 6 Sphingomyelins, 5 Aminoacids and 5 Biogenic Amines. Thirteen consensus metabolites were identified through network-based analysis, including 1 biogenic amine, 2 lysophosphatidylcholines and 10 glycerophospholipids. A predictive model using these metabolites showed an AUC-ROC of 0.992 (CI: 0.965–1.000). Conclusion: These results highlight deep metabolic remodeling in FD and confirm the potential of omics-based approaches in lysosomal diseases to reveal clinical and biological associations to generate pathophysiological hypotheses.

Platelet and myeloid cell phenotypes in a rat model of Fabry disease

Fabry disease results from a deficiency of the lysosomal enzyme ⍺-Galactosidase-A (⍺-Gal A) and is estimated to occur in approximately 1:4100 live births. Characteristic of the disease is the accumulation of α-Gal-A substrates, primarily the glycosphingolipids (GSLs) globotriaosylceramide and globotriaosylsphingosine. Thrombotic events are a significant concern for Fabry patients, with strokes contributing to a significant decrease in overall lifespan. Currently, the mechanisms underlying the increased risk of thrombotic events experienced by Fabry patients are incompletely defined. Using a rat model of Fabry disease, we provide an improved understanding of the mechanisms linking GSL accumulation to thrombotic risk. We found that ⍺-Gal A-deficient rats accumulate myeloid-derived leukocytes at sites of GSL accumulation, including in the bone marrow and circulation, and that myeloid-derived leukocyte and megakaryocyte populations were prominent among cell types that accumulated GSLs. In the circulation, ⍺-Gal A-deficient rats had increases in cytokine-producing cell types and a corresponding elevation of pro-inflammatory cytokines. Lastly, circulating platelets from ⍺-Gal A-deficient rats accumulated a similar set of ⍺-Galactosidase-A substrates as was observed in megakaryocytes in the bone marrow, and exhibited increased platelet binding to fibrinogen in microfluidic and flow cytometric assays.

X Chromosome Inactivation in Carriers of Fabry Disease: Review and Meta-Analysis

Anderson-Fabry disease is an X-linked inborn error of glycosphingolipid catabolism caused by a deficiency of α-galactosidase A. The incidence ranges between 1: 40,000 and 1:117,000 of live male births. In Italy, an estimate of incidence is available only for the north-western Italy, where it is of approximately 1:4000. Clinical symptoms include angiokeratomas, corneal dystrophy, and neurological, cardiac and kidney involvement. The prevalence of symptomatic female carriers is about 70%, and in some cases, they can exhibit a severe phenotype. Previous studies suggest a correlation between skewed X chromosome inactivation and symptoms in carriers of X-linked disease, including Fabry disease. In this review, we briefly summarize the disease, focusing on the clinical symptoms of carriers and analysis of the studies so far published in regards to X chromosome inactivation pattern, and manifesting Fabry carriers. Out of 151 records identified, only five reported the correlation between the analysis of XCI in leukocytes and the related phenotype in Fabry carriers, in particular evaluating the Mainz Severity Score Index or cardiac involvement. The meta-analysis did not show any correlation between MSSI or cardiac involvement and skewed XCI, likely because the analysis of XCI in leukocytes is not useful for predicting the phenotype in Fabry carriers.

Defective lysosomal storage in Fabry disease modifies mitochondrial structure, metabolism and turnover in renal epithelial cells

Fabry disease (FD) is an X-linked lysosomal storage disorder. Deficiency of the lysosomal enzyme alpha-galactosidase (GLA) leads to accumulation of potentially toxic globotriaosylceramide (Gb3) on a multisystem level. Cardiac and cerebrovascular abnormalities as well as progressive renal failure are severe, life-threatening long-term complications. The complete pathophysiology of chronic kidney disease (CKD) in FD and the role of tubular involvement for its progression are unclear. We established human renal tubular epithelial cell lines from the urine of male FD patients and male controls. The renal tubular system is rich in mitochondria and involved in transport processes at high-energy costs. Our studies revealed fragmented mitochondria with disrupted cristae structure in FD patient cells. Oxidative stress levels were elevated and oxidative phosphorylation was upregulated in FD pointing at enhanced energetic needs. Mitochondrial homeostasis and energy metabolism revealed major changes as evidenced by differences in mitochondrial number, energy production and fuel consumption. The changes were accompanied by activation of the autophagy machinery in FD. Sirtuin1, an important sensor of (renal) metabolic stress and modifier of different defense pathways, was highly expressed in FD. Our data show that lysosomal FD impairs mitochondrial function and results in severe disturbance of mitochondrial energy metabolism in renal cells. This insight on a tissue-specific level points to new therapeutic targets which might enhance treatment efficacy.

Fabry disease exacerbates renal interstitial fibrosis after unilateral ureteral obstruction via impaired autophagy and enhanced apoptosis

Background

Fabry disease is a rare X-linked genetic lysosomal disorder caused by mutations in the GLA gene encoding alpha-galactosidase A. Despite some data showing that profibrotic and proinflammatory cytokines and oxidative stress could be involved in Fabry disease-related renal injury, the pathogenic link between metabolic derangement within cells and renal injury remains unclear.

Methods

Renal fibrosis was triggered by unilateral ureteral obstruction (UUO) in mice with Fabry disease to investigate the pathogenic mechanism leading to fibrosis in diseased kidneys.

Results

Compared to kidneys of wild-type mice, lamellar inclusion bodies were recognized in proximal tubules of mice with Fabry disease. Sirius red and trichrome staining revealed significantly increased fibrosis in all UUO kidneys, though it was more prominent in obstructed Fabry kidneys. Renal messenger RNA levels of inflammatory cytokines and profibrotic factors were increased in all UUO kidneys compared to sham-operated kidneys but were not significantly different between UUO control and UUO Fabry mice. Protein levels of Nox2, Nox4, NQO1, catalase, SOD1, SOD2, and Nrf2 were not significantly different between UUO control and UUO Fabry kidneys, while the protein contents of LC3-II and LC3-I and expression of Beclin1 were significantly decreased in UUO kidneys of Fabry disease mouse models compared with wild-type mice. Notably, TUNEL-positive cells were elevated in obstructed kidneys of Fabry disease mice compared to wild-type control and UUO mice.

Conclusion

These findings suggest that impaired autophagy and enhanced apoptosis are probable mechanisms involved in enhanced renal fibrosis under the stimulus of UUO in Fabry disease.

Biomarkers in Fabry Disease. Implications for Clinical Diagnosis and Follow-up

Fabry disease (FD) is a lysosomal storage disorder caused by deficient alpha-galactosidase A activity in the lysosome due to mutations in the GLA gene, resulting in gradual accumulation of globotriaosylceramide and other derivatives in different tissues. Substrate accumulation promotes different pathogenic mechanisms in which several mediators could be implicated, inducing multiorgan lesions, mainly in the kidney, heart and nervous system, resulting in clinical manifestations of the disease. Enzyme replacement therapy was shown to delay disease progression, mainly if initiated early. However, a diagnosis in the early stages represents a clinical challenge, especially in patients with a non-classic phenotype, which prompts the search for biomarkers that help detect and predict the evolution of the disease. We have reviewed the mediators involved in different pathogenic mechanisms that were studied as potential biomarkers and can be easily incorporated into clinical practice. Some accumulation biomarkers seem to be useful to detect non-classic forms of the disease and could even improve diagnosis of female patients. The combination of such biomarkers with some response biomarkers, may be useful for early detection of organ injury. The incorporation of some biomarkers into clinical practice may increase the capacity of detection compared to that currently obtained with the established diagnostic markers and provide more information on the progression and prognosis of the disease.

Globotrioasylsphingosine Levels and Optical Coherence Tomography Angiography in Fabry Disease Patients

Background: To date, there are no studies associating the dried blood spot (DBS) levels of globotrioasylsphingosine (lysoGb3) with quantitative optical coherence tomography angiography (OCTA) parameters in Fabry disease (FD) patients. Here, we aimed to investigate the association between OCTA vessel density (VD), vessel length density (VLD) with DBS lysoGb3. Methods: A retrospective, single center analysis of all consecutive FD patients enrolled at the Department of Ophthalmology of the University Hospital of Zurich from 1 December 2017 to 9 September 2020. An association between VD and VLD detected by OCTA and lysoGb3 was investigated using a linear mixed model. Results: A total of 57 FD patients (23 male, 34 female; 109 eyes) were included. Forty-one patients suffered from the classic phenotype and 16 from the later-onset phenotype. LysoGb3 inversely correlated with VD and VLD in both the superficial (VD: p = 0.034; VLD: p = 0.02) and deep capillary plexus (VD: p = 0.017; VLD: p = 0.018) in the overall FD cohort. Conclusions: Our study shows an association between lysoGb3 and OCTA VD and VLD. This supports the hypothesis that quantitative OCTA parameters might be useful as diagnostic biomarkers for evaluating systemic involvement in FD, and possibly other diseases.

Sphingolipids as Regulators of Neuro-Inflammation and NADPH Oxidase 2

Neuro-inflammation accompanies numerous neurological disorders and conditions where it can be associated with a progressive neurodegenerative pathology. In a similar manner, alterations in sphingolipid metabolism often accompany or are causative features in degenerative neurological conditions. These include dementias, motor disorders, autoimmune conditions, inherited metabolic disorders, viral infection, traumatic brain and spinal cord injury, psychiatric conditions, and more. Sphingolipids are major regulators of cellular fate and function in addition to being important structural components of membranes. Their metabolism and signaling pathways can also be regulated by inflammatory mediators. Therefore, as certain sphingolipids exert distinct and opposing cellular roles, alterations in their metabolism can have major consequences. Recently, regulation of bioactive sphingolipids by neuro-inflammatory mediators has been shown to activate a neuronal NADPH oxidase 2 (NOX2) that can provoke damaging oxidation. Therefore, the sphingolipid-regulated neuronal NOX2 serves as a mechanistic link between neuro-inflammation and neurodegeneration. Moreover, therapeutics directed at sphingolipid metabolism or the sphingolipid-regulated NOX2 have the potential to alleviate neurodegeneration arising out of neuro-inflammation.

Reversal of the Inflammatory Responses in Fabry Patient iPSC-Derived Cardiovascular Endothelial Cells by CRISPR/Cas9-Corrected Mutation

The late-onset type of Fabry disease (FD) with GLA IVS4 + 919G > A mutation has been shown to lead to cardiovascular dysfunctions. In order to eliminate variations in other aspects of the genetic background, we established the isogenic control of induced pluripotent stem cells (iPSCs) for the identification of the pathogenetic factors for FD phenotypes through CRISPR/Cas9 genomic editing. We adopted droplet digital PCR (ddPCR) to efficiently capture mutational events, thus enabling isolation of the corrected FD from FD-iPSCs. Both of these exhibited the characteristics of pluripotency and phenotypic plasticity, and they can be differentiated into endothelial cells (ECs). We demonstrated the phenotypic abnormalities in FD iPSC-derived ECs (FD-ECs), including intracellular Gb3 accumulation, autophagic flux impairment, and reactive oxygen species (ROS) production, and these abnormalities were rescued in isogenic control iPSC-derived ECs (corrected FD-ECs). Microarray profiling revealed that corrected FD-derived endothelial cells reversed the enrichment of genes in the pro-inflammatory pathway and validated the downregulation of NF-κB and the MAPK signaling pathway. Our findings highlighted the critical role of ECs in FD-associated vascular dysfunctions by establishing a reliable isogenic control and providing information on potential cellular targets to reduce the morbidity and mortality of FD patients with vascular complications.

Ferroptosis and Its Modulation by Autophagy in Light of the Pathogenesis of Lysosomal Storage Diseases

Ferroptosis is one of the recently described types of cell death which is dependent on many factors, including the accumulation of iron and lipid peroxidation. Its induction requires various signaling pathways. Recent discovery of ferroptosis induction pathways stimulated by autophagy, so called autophagy-dependent ferroptosis, put our attention on the role of ferroptosis in lysosomal storage diseases (LSD). Lysosome dysfunction, observed in these diseases, may influence ferroptosis efficiency, with as yet unknown consequences for the function of cells, tissues, and organisms, due to the effects of ferroptosis on physiological and pathological metabolic processes. Modulation of levels of ferrous ions and enhanced oxidative stress, which are primary markers of ferroptosis, are often described as processes associated with the pathology of LSD. Inhibition of autophagy flux and resultant accumulation of autophagosomes in neuronopathic LSD may induce autophagy-dependent ferroptosis, indicating a considerable contribution of this process in neurodegeneration. In this review article, we describe molecular mechanisms of ferroptosis in light of LSD, underlining the modulation of levels of ferroptosis markers in these diseases. Furthermore, we propose a hypothesis about the possible involvement of autophagy-dependent ferroptosis in these disorders.

RIPK3 Contributes to Lyso-Gb3-Induced Podocyte Death

Fabry disease is a lysosomal storage disease with an X-linked heritage caused by absent or decreased activity of lysosomal enzymes named alpha-galactosidase A (α-gal A). Among the various manifestations of Fabry disease, Fabry nephropathy significantly affects patients' morbidity and mortality. The cellular mechanisms of kidney damage have not been elusively described. Necroptosis is one of the programmed necrotic cell death pathways and is known to play many important roles in kidney injury. We investigated whether RIPK3, a protein phosphokinase with an important role in necroptosis, played a crucial role in the pathogenesis of Fabry nephropathy both in vitro and in vivo. The cell viability of podocytes decreased after lyso-Gb3 treatment in a dose-dependent manner, with increasing RIPK3 expression. Increased reactive oxygen species (ROS) generation after lyso-Gb3 treatment, which was alleviated by GSK'872 (a RIPK3 inhibitor), suggested a role of oxidative stress via a RIPK3-dependent pathway. Cytoskeleton rearrangement induced by lyso-Gb3 was normalized by the RIPK3 inhibitor. When mice were injected with lyso-Gb3, increased urine albuminuria, decreased podocyte counts in the glomeruli, and effaced foot processes were observed. Our results showed that lyso-Gb3 initiated albuminuria, a clinical manifestation of Fabry nephropathy, by podocyte loss and subsequent foot process effacement. These findings suggest a novel pathway in Fabry nephropathy.

Chloroquine may induce endothelial injury through lysosomal dysfunction and oxidative stress

COVID-19 is a pandemic with no end in sight. There is only one approved antiviral agent but global stocks are deemed insufficient. Despite in vitro antiviral activity, clinical trials of chloroquine and hydroxychloroquine were disappointing, and they may even impair outcomes. Chloroquine causes zebroid deposits reminiscent of Fabry disease (α-galactosidase A deficiency) and endothelial cells are key targets of COVID-19. We have explored the effect of chloroquine on cultured endothelial cells and its modulation by recombinant α-galactosidase A (agalsidase). Following dose-response studies, 0.5 μg/mL chloroquine was added to cultured human endothelial cells. Neutral red and Lysotracker were used to assess lysosomes. Cytotoxicity was evaluated by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) - MTT assay and cell stress by assessing reactive oxygen species (ROS) and nitric oxide (NO). In endothelial cells, chloroquine induced dose-dependent cytotoxicity at in vitro test concentrations for COVID-19 therapy. At a sublethal concentration, chloroquine significantly induced the accumulation of acid organelles (P < 0.05), increased ROS levels, and decreased NO production (P < 0.05). These adverse effects of chloroquine on endothelial cell biology were decreased by agalsidase-β (P < 0.05). Chloroquine-induced endothelial cell cytotoxicity and stress is attenuated by agalsidase-β treatment. This suggests that endothelial cell injury may contribute to the failure of chloroquine as therapy for COVID-19 and may be at least in part related to causing dysfunction of the lysosomal enzyme α-galactosidase A.

Increased Serum Interleukin-6 and Tumor Necrosis Factor Alpha Levels in Fabry Disease: Correlation with Disease Burden

OBJECTIVES

Fabry disease (FD) is an X-linked lysosomal disease caused by variants of the GLA gene; the formation of defective alpha-galactosidase A contributes to the accumulation of substrates in several organs. Chronic inflammation is thought to contribute to organ damage in FD patients.

METHODS

In total, 36 classic FD patients (15 men/21 women) and 25 healthy controls (20 men/8 women) were assessed. The Mainz Severity Score Index (MSSI) was established after conducting interviews with the patients and chart review. Serum IL-6, IL-1β, and TNF-α levels were evaluated in both groups.

RESULTS

The mean age (years) for FD patients was 43.1±15.4 and that for the controls was 47.4±12.2 (p>0.05). Twenty-two patients (59.5%) were treated with enzyme replacement therapy (ERT). Serum IL-6 and TNF-α levels were significantly higher in FD patients than in the controls. Patients treated with ERT had higher serum IL-6 and TNF-α levels than those not treated with ERT. There was no difference in the serum IL-1β levels between patients treated with ERT and those who were not. The MSSI scores in the patients were correlated with serum levels of IL-6 (r=0.60, p<0.001) and TNF-α (r=0.45, p<0.001).

CONCLUSION

FD was associated with elevated serum levels of IL-6 and TNF-α in this cohort. The FD patients treated with ERT, particularly, women, exhibited higher levels of serum IL-6 and TNF-α than those not treated with ERT; the serum IL-6 and TNF-α levels were correlated with the MSSI scores reflecting greater disease burden.

Patients with Gaucher disease display systemic oxidative stress dependent on therapy status

Gaucher disease is an autosomal recessive metabolic disorder caused by mutations in GBA1, which encodes for the lysosomal hydrolase enzyme, β-glucocerebrosidase. The resulting misfolded protein can trigger endoplasmic reticulum stress and an unfolded protein response within the affected cells. The enzyme deficiency leads to accumulation of its substrates, glucosylceramide and glucosylsphingosine, within macrophage lysosomes and with prominent disease manifestations in macrophage rich tissues. Resultant lysosomal pathology and impaired autophagy leads to redox imbalance, mitochondrial dysfunction and intracellular oxidative stress. Here we have systematically examined a role for oxidative stress in individuals affected by Gaucher disease. We compared multiple oxidative stress biomarkers in plasma and red blood cell samples from patients who are currently untreated, with those who are stable on standard-of-care therapy, and with healthy controls. We found significant differences in key oxidative stress biomarkers in untreated patients compared to healthy control. In treated patients, results generally fell between the controls and the untreated patients. Interestingly, even asymptomatic and minimally symptomatic untreated patients had evidence of significant systemic oxidative stress. We conclude that underlying oxidative stress may contribute to Gaucher disease pathophysiology including long-term adverse outcomes such as Parkinsonism and malignancies. Therapies targeting oxidative stress may prove useful as adjuvant treatments for Gaucher disease and other lysosomal storage disorders.

Fabry disease patients have an increased risk of stroke in the COVID-19 ERA. A hypothesis

Stroke is a severe and frequent complication of Fabry disease (FD), affecting both males and females. Cerebrovascular complications are the end result of multiple and complex pathophysiology mechanisms involving endothelial dysfunction and activation, development of chronic inflammatory cascades leading to a prothrombotic state in addition to cardioembolic stroke due to cardiomyopathy and arrhythmias. The recent coronavirus disease 2019 outbreak share many overlapping deleterious pathogenic mechanisms with those of FD and therefore we analyze the available information regarding the pathophysiology mechanisms of both disorders and hypothesize that there is a markedly increased risk of ischemic and hemorrhagic cerebrovascular complications in Fabry patients suffering from concomitant SARS-CoV-2 infections.

The role of Immunity in Fabry Disease and Hypertension: A Review of a Novel Common Pathway

Fabry disease is a progressive, X-linked inherited lysosomal storage disorder where accumulation of glycosphingolipids increases the risk for early cardiovascular complications, including heart failure, stroke, and end stage renal disease. Besides disease-specific therapy, blood pressure (BP) control is of central importance in Fabry disease to reduce disease progression and improve prognosis. Both Fabry disease and hypertension are characterized by the activation of the innate component of the immune system, with Toll-like receptor 4 (TLR4) as a common trigger to the inflammatory cascade. The renin-angiotensin system (RAS) participates in the establishment of low-grade chronic inflammation and redox unbalance that contribute to organ damage in the long term. Besides exploiting the anti-inflammatory effects of RAS blockade and enzyme replacement therapy, targeted therapies acting on the immune system represent an appealing field of research in these conditions. The aim of this narrative review is to examine the issue of hypertension in the setting of Fabry disease, focusing on the possible determinants of their reciprocal relationship, as well as on the related clinical and therapeutic implications.

AA amyloidosis associated with Fabry disease

BACKGROUND

Fabry disease (FD) is the second most common lysosomal storage disorder, carrying a large morbidity and mortality. It has been recently reported that lysosomal storage disorders could cause inflammation and, subsequently, AA amyloidosis (AAA). Our aim was to describe AAA cases occurring in the course of FD.

PATIENTS AND METHODS

We described two patients displaying both AAA and FD and an additional case from the literature.

RESULTS

Three female patients originating from Europe (n = 2) and Algeria (n = 1) harboured heterozygous GLA mutations. The median age at AAA diagnosis was 61 years old. The diagnosis of Fabry was made before the diagnosis of AAA (n = 1) or concomitantly (n = 2). At AAA diagnosis, two patients displayed a nephrotic syndrome; all had inflammation.

CONCLUSION

Fabry disease can be associated with AAA, suggesting that an inflammatory component could exist in this genetic disease.

Therapeutic advances in Fabry disease: The future awaits

Fabry disease (FD) is an X-linked disorder caused by mutations in GLA gene responsible for coding of the lysosomal enzyme alpha-galactosidase A(α-GAL). The resultant accumulation of globotriaosylceramide (Gb-3) leads to multisystemic disease including progressive chronic kidney disease, hypertrophic cardiomyopathy, stroke, angiokeratomas and corneal whorls. Current treatments include enzyme replacement therapy (ERT), along with recent advent of chaperone therapy. ERT has not shown to have dramatic improvement in outcomes for all organ systems, with benefit mostly seen in kidney disease and reduction in left ventricular hypertrophy. ERT, however, is associated with formation of anti-drug antibodies and requirement of long-term venous access, while chaperone therapy can only be used in amenable mutations. A multitude of therapies are now under investigation in various phases of clinical trials. These include pegylated form of α-GAL (pegunigalsidase alpha), gene therapy (both in-vivo and ex-vivo methods), mRNA therapy (inducing production of α-GAL) and substrate reduction therapy (inhibitors of glucosylceramide synthase leading to reduction of Gb-3). This review encapsulates literature pertaining to current and investigational therapies for FD.

Cardiac manifestations in patients with classical or cardiac subtype of Fabry disease

BACKGROUND

Fabry disease (FD) is an X-linked lysosomal storage disorder engendered by a deficiency of the enzyme α-galactosidase A, leading to systemic accumulation of glycolipids. Studies have reported that the cardiac subtype of FD has a later onset and minimal extracardiac involvement. However, whether the severity of cardiac involvement differs between the classic and cardiac subtypes of FD remains unclear.

METHODS

We enrolled consecutive patients with classic FD (n = 22; median age [25th-75th percentile], 47.0 [32.75-56.25] years; men, 72.7%) as well as age- and sex-matched patients with a later-onset cardiac subtype of FD who were selected from our cohort of patients with IVS4 919G>A mutation. FD was diagnosed on the basis of clinical symptoms/signs and pedigree screening of index case, plasma α-galactosidase activity, and molecular analysis. Data on clinical manifestations, laboratory findings, and echocardiogram findings were collected before enzyme replacement treatment. Disease severity was evaluated using the Mainz Severity Score Index score.

RESULTS

All female patients demonstrated heterozygous mutations, with five, one, and four of them showing normal α-galactosidase activity, classic FD, and cardiac subtype of FD, respectively. The distributions of left ventricular performance indices and comorbidities, including hypertension, diabetes mellitus, and dyslipidemia, were similar between the two groups. Moreover, MSSI cardiovascular scores did not differ significantly between the groups (classic vs cardiac subtype, 10.0 [2.0-12.5] vs 10.5 [9.0-15.25]; p = 0.277).

CONCLUSION

Cardiac manifestations are similar between patients with classic and cardiac subtype of FD.