Elevated Inflammatory Plasma Biomarkers in Patients With Fabry Disease: A Critical Link to Heart Failure With Preserved Ejection Fraction

Background Because systemic inflammation and endothelial dysfunction lead to heart failure with preserved ejection fraction, we characterized plasma levels of inflammatory and cardiac remodeling biomarkers in patients with Fabry disease ( FD ). Methods and Results Plasma biomarkers were studied in multicenter cohorts of patients with FD (n=68) and healthy controls (n=40). Plasma levels of the following markers of inflammation and cardiac remodeling were determined: tumor necrosis factor ( TNF ), TNF receptor 1 ( TNFR 1) and 2 ( TNFR 2), interleukin-6, matrix metalloprotease-2 ( MMP -2), MMP -8, MMP -9, galectin-1, galectin-3, B-type natriuretic peptide ( BNP ), midregional pro-atrial natriuretic peptide ( MR -pro ANP ), and globotriaosylsphingosine. Clinical profile, cardiac magnetic resonance imaging, and echocardiogram were reviewed and correlated with biomarkers. Patients with FD had elevated plasma levels of BNP , MR -pro ANP , MMP -2, MMP -9, TNF , TNFR 1, TNFR 2, interleukin-6, galectin-1, globotriaosylsphingosine, and analogues. Plasma TNFR 2, TNF , interleukin-6, MMP -2, and globotriaosylsphingosine were elevated in FD patients with left ventricular hypertrophy, whereas diastolic dysfunction correlated with higher BNP , MR -pro ANP , and MMP -2 levels. Patients with late gadolinium enhancement on cardiac magnetic resonance imaging had greater levels of BNP , MR -pro ANP , TNFR 1, TNFR 2, and MMP -2. Plasma BNP , MR -pro ANP , MMP -2, MMP -8, TNF , TNFR 1, TNFR 2, galectin-1, and galectin-3 were elevated in patients with renal dysfunction. Patients undergoing enzyme replacement therapy who have more severe disease had higher MMP -2, TNF , TNFR 1, TNFR 2, and globotriaosylsphingosine analogue levels. Conclusions Inflammatory and cardiac remodeling biomarkers are elevated in FD patients and correlate with disease progression. These features are consistent with a phenotype dominated by heart failure with preserved ejection fraction and suggest a key pathogenic role of systemic inflammation in FD .

Gender-specific plasma proteomic biomarkers in patients with Anderson-Fabry disease

AIMS

Anderson-Fabry disease (AFD) is an important X-linked metabolic disease resulting in progressive end-organ involvement, with cardiac disease being the dominant determinant of survival in a gender-dependent manner. Recent epidemiological screening for AFD suggests the prevalence is much higher than previously recognized, with estimates of 1:3000. Our aim was to discover novel plasma biomarker signatures in adult patients with AFD.

METHODS AND RESULTS

We used an unbiased proteomic screening approach to discover novel plasma biomarker signatures. In the discovery cohort of 46 subjects, 14 healthy controls and 32 patients with AFD, we used a mass spectrometry iTRAQ proteomic approach followed by multiple reaction monitoring (MRM) assays to identify biomarkers. Of the 38 protein groups discovered by iTRAQ, 18 already had existing MRM assays. Based on MRM, we identified an eight-protein biomarker panel (22 kDa protein, afamin, α1 antichymotrypsin, apolipoprotein E, β-Ala His dipeptidase, haemoglobin α-2, isoform 1 of sex hormone-binding globulin, and peroxiredoxin 2) that was very specific and sensitive for male AFD patients. In female AFD patients, we identified a nine-marker panel of proteins with only three proteins, apolipoprotein E, haemoglobin α-2, and peroxiredoxin 2, common to both genders, suggesting a gender-specific alteration in plasma biomarkers in patients with AFD. The biomarkers were validated in plasma samples from 48 subjects using MRM, and they performed inferiorly in patients with heart failure.

CONCLUSIONS

We have identified gender-specific plasma protein biomarker panels that are specific and sensitive for the AFD phenotype. The gender-specific panels offer important insight into potential differences in pathophysiology and prognosis between males and females with AFD.

Molecular damage in Fabry disease: characterization and prediction of alpha-galactosidase A pathological mutations

Loss-of-function mutations of the enzyme alpha-galactosidase A (GLA) causes Fabry disease (FD), that is a rare and potentially fatal disease. Identification of these pathological mutations by sequencing is important because it allows an early treatment of the disease. However, before taking any treatment decision, if the mutation identified is unknown, we first need to establish if it is pathological or not. General bioinformatic tools (PolyPhen-2, SIFT, Condel, etc.) can be used for this purpose, but their performance is still limited. Here we present a new tool, specifically derived for the assessment of GLA mutations. We first compared mutations of this enzyme known to cause FD with neutral sequence variants, using several structure and sequence properties. Then, we used these properties to develop a family of prediction methods adapted to different quality requirements. Trained and tested on a set of known Fabry mutations, our methods have a performance (Matthews correlation: 0.56-0.72) comparable or better than that of the more complex method, Polyphen-2 (Matthews correlation: 0.61), and better than those of SIFT (Matthews correl.: 0.54) and Condel (Matthews correl.: 0.51). This result is validated in an independent set of 65 pathological mutations, for which our method displayed the best success rate (91.0%, 87.7%, and 73.8%, for our method, PolyPhen-2 and SIFT, respectively). These data confirmed that our specific approach can effectively contribute to the identification of pathological mutations in GLA, and therefore enhance the use of sequence information in the identification of undiagnosed Fabry patients.

Gene Mutations Versus Clinically Relevant Phenotypes

Background—

Currently, no method is available to identify α-galactosidase A (agalA) mutations determining clinically relevant Fabry disease. In our largest European Fabry cohort, we investigated whether a biomarker, specific for the defect, could stratify persons at risk.

Methods and Results—

A total of 124 individuals with agalA mutations were investigated with a comprehensive clinical workup, genetic analysis, and laboratory testing, including measurements of agalA activity and lyso-Gb3 (degradation product of the accumulating Gb3). Additionally, an extensive family screening with a clinical workup of relatives was performed. The patient population was divided into 2 samples: previously described mutations (n=72) and novel mutations (n=52). The patients with previously described mutations were subdivided into 2 groups: classical mutations, which were known to cause the classic type of Fabry disease with specific symptoms and a high risk for major events in all 3 main organs (heart, kidney, and central nervous system), and atypical mutations without the typical presentation. All patients with atypical mutations (n=17) had lower lyso-Gb3 levels than any of the patients with classical Fabry disease (n=55). A cutoff value of 2.7 ng/mL separated the 2 groups. Six out of 52 patients with novel mutations showed a lyso-Gb3 level <2.7 ng/mL. Clinical investigation, blinded to lyso-Gb3 results, revealed no classic organ involvement in these patients or their relatives. In contrast, the characterization of patients with lyso-Gb3≥2.7ng/mL suggested classical Fabry mutations in most of the patients (93%).

Conclusions—

Our data show that the biomarker lyso-Gb3 may identify the clinically relevant agalA mutations leading to Fabry disease.

Lyso-Gb3 Indicates that the Alpha-Galactosidase A Mutation D313Y is not Clinically Relevant for Fabry Disease

The X-chromosomal-linked lysosomal storage disorder Fabry disease can lead to life-threatening manifestations. The pathological significance of the Fabry mutation D313Y is doubted, because, in general, D313Y patients do not present clinical manifestations conformable with Fabry disease. This is in contrast to the analysis of the alpha-galactosidase A activity, which is reduced in D313Y patients. We report a comprehensive clinical, biochemical and molecular genetic analysis of two patients with a D313Y mutation. The alpha-galactosidase A activity was reduced in both patients. No Fabry symptoms or Fabry organ involvement was detected in these patients. The new biomarker lyso-Gb3, severely increased in classical Fabry patients, was determined and in both patients lyso-Gb3 was below the average of a normal population.Our data for the first time not only clinically but also biochemically supports the hypothesis that the D313Y mutation is not a classical one, but a rare variant mutation.

Cardiac energy metabolism is disturbed in Fabry disease and improves with enzyme replacement therapy using recombinant human galactosidase A

AIMS

In vitro studies have shown impairment of energy metabolism in cardiac fibroblasts from Fabry patients. A recent in vivo study reported an association between cardiac energy metabolism and increased myocardial mass in Fabry patients. We therefore assessed possible disturbances of cardiac energy metabolism in Fabry patients by in vivo (31)P-MR-spectroscopy. Additionally, the effect of enzyme replacement therapy (ERT) on cardiac energetics was tested.

METHODS AND RESULTS

Twenty-three patients (41 ± 9 years; 10 females) with genetically proven Fabry disease were examined with a 1.5 T Scanner, and compared with an age-matched healthy control group. Eight patients underwent ERT and had follow-up examinations after 3 and 14 months. The high-energy phosphate molecules phosphocreatine (PCr) and adenosine triphosphate (ATP) were quantified in localized 31P-spectra by SLOOP (spectral localization with optimum point spread function). Cine- and late gadolinium enhancement (LGE) studies were also performed. When compared with healthy controls, Fabry patients demonstrated reduced PCr- (6.1 ± 1.9 vs. 8.8 ± 2.6 mmol/kg; P = 0.003) and ATP concentrations (3.9 ± 1.5 vs. 4.6 ± 1.0 mmol/kg; P = 0.048). During ERT, PCr concentrations increased (7.1 ± 1.5 mmol/kg vs. 6.1 ± 1.9; P < 0.05) and left ventricular mass decreased (215 ± 55 vs. 185 ± 45 g; P = 0.012). Disturbances in cardiac energetics were not correlated to the presence or absence of cardiac fibrosis on LGE.

CONCLUSION

Cardiac energy metabolism is disturbed in Fabry disease; this may play an important role in the pathogenesis of Fabry cardiomyopathy. Enzyme replacement therapy ameliorates energetic depression.