Homocysteine and tissue factor pathway inhibitor levels in patients with Fabry's disease

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.

High incidence of co-existing factors significantly modifying the phenotype in patients with Fabry disease

Fabry disease results from deficiency of the lysosomal enzyme alpha-galactosidase A. The families of 11 index cases were screened by enzyme and molecular assays. Further clinical and laboratory investigations were carried out in all cases. Including 33 new patients, a total of 28 females (Age 25,82 ± 12,1 Range 8-46) and 16 males (Age 24,56 ± 15,04 Range 2-48) were investigated. Ten different disease-causing variants were found two of them being novel. One patient had co-existing familial mediteranian fever, one had celiac disease and three had rheumatological disorders. Lipoprotein (a) levels were elevated in 17,6%, homocysteine in 22,2%, total and low density cholesterol in 12% and antithrombin 3 levels were elevated in 13,3%. One patient was found to be heterozygous for prothrombin p.G20210A disease-causing variant (5,8%) and two for factor V Leiden disease-causing variant (11,7%). Anticardiolipin IgM antibody was found to be positive in 11,7%. The patients with abnormal cranial imaging were also noticed to have additional risk factors for thrombosis. This study provides the largest data about Fabry patients from Turkey and implies that co-existing risk factors unrelated to Fabry Disease have significant association with the presence of clinical symptoms in females and might cause an early and severe clinical course in males.

Genetic determinants of tissue factor pathway inhibitor plasma levels

Tissue factor pathway inhibitor (TFPI) impedes early stages of the blood coagulation response, and low TFPI plasma levels increase the risk of thrombosis. TFPI plasma levels are heritable, but specific genetic determinants are unclear. We conducted a comprehensive review of genetic risk factors for TFPI plasma levels and identified 26 studies. We included 16 studies, as well as results from two unpublished genome-wide studies, in random effects meta-analyses of four commonly reported genetic variants in TFPI and its promoter (rs5940, rs7586970/rs8176592, rs10931292, and rs10153820) and 10 studies were summarised narratively. rs5940 was associated with all measures of TFPI (free, total, and activity), and rs7586970 was associated with total TFPI. Neither rs10931292 nor rs10153820 showed evidence of association. The narrative summary included 6 genes and genetic variants (P151L mutation in TFPI, PROS1, F5, APOE, GLA, and V617F mutation in JAK2) as well as a genome-wide linkage study, and suggested future research directions. A limitation of the systematic review was the heterogeneous measurement of TFPI. Nonetheless, our review found robust evidence that rs5940 and rs7586970 moderate TFPI plasma levels and are candidate risk factors for thrombosis, and that the regulation of TFPI plasma levels involves genetic factors beyond the TFPI gene.

Homocysteine and erythrocyte sedimentation rate correlate with cerebrovascular disease in fabry disease

BACKGROUND

Cerebrovascular disease (CVD) is a common clinical problem in Fabry disease; however, expression of this disease manifestation is not uniform and risk factors for its development are not well studied. A number of common CVD risk factors are known in the general population, and these may also play a role in the development of CVD in Fabry disease.

AIM

To evaluate the potential associations between various risk factors and CVD in patients with Fabry disease.

METHODS AND RESULTS

Thirty-two Fabry disease patients were studied, with 15 having evidence of CVD. T-tests were used to compare the positive and negative CVD groups and logistic regression was used to look for correlations with CVD history. CVD-positive patients were older (49.73 vs. 37.59 years, p<0.001) and had worse renal function (GFR 61.53 vs. 96.61 mL/min/1.73 m(2), p < 0.005), higher homocysteine (17.79 vs. 10.53 μmol/L, p < 0.05) and erythrocyte sedimentation rate (ESR) levels (23.8 vs. 7.64 mm/h, p < 0.001), and elevated Mainz Severity Score Index (MSSI) scores (23.8 vs. 11.8, p < 0.001). Correlations were found between age (odds ratio (OR) 1.11), DTPA glomerular filtration rate (OR 0.95), homocysteine concentration (OR 1.22), ESR (OR 1.16) and the MSSI (OR 1.19) scores with a positive CVD history (all p < 0.05).

CONCLUSION

Elevated homocysteine and ESR are independent risk factors for CVD in Fabry disease. This finding adds to our ability to predict those patients with Fabry disease who are at a higher risk of developing CVD, and may be an aid in deciding which patients should have primary CVD prevention therapies.

Evaluation of oxidative stress markers and cardiovascular risk factors in Fabry Disease patients

Fabry Disease, an X-linked inborn error of metabolism, is characterized by progressive renal insufficiency, with cardio and cerebrovascular involvement. Homocysteine (Hcy) is considered a risk factor for vascular diseases, but the mechanisms by which it produces cardiovascular damage are still poorly understood. Regarding the vascular involvement in FD patients, the analysis of factors related to thromboembolic events could be useful to improving our understanding of the disease. The aim of this study was to evaluate plasma Hcy and other parameters involved in the methionine cycle, as well as oxidative stress markers. The sample consisted of a group of 10 male FD patients and a control group of 8 healthy individuals, paired by age. Venous blood was collected for Hcy determination, molecular analysis, identification of thiobarbituric acid reactive substances, total glutathione and antioxidant enzymes activity, as well as vitamins quantification. Comparative analysis of FD patients versus the control group indicated hyperhomocysteinemia in 8 of the 10 FD patients, as well as a significant increase in overall glutathione levels and catalase activity. It is inferred that FD patients, apart from activation of the antioxidant system, present increased levels of plasma Hcy, although this is probably unrelated to common alterations in the methionine cycle.

Vasculopathy in patients with Fabry disease: current controversies and research directions

Fabry disease is an X-linked lysosomal storage disorder due to deficiency of the enzyme alpha-galactosidase A. The principal clinical manifestations of Fabry disease consist of cardiovascular complications including cerebrovascular, renal and cardiac disease but the pathophysiology of this specific vasculopathy is unclear. With the development of targeted treatment for Fabry disease, i.e. enzyme replacement therapy, it has become apparent that the removal of stored glycosphingolipid from the endothelial cells does not prevent progression of vascular disease in many patients. The aim of this study is to review the current available literature on vascular function tests, imaging and pathology studies and propose a hypothesis on the evolution of arterial complications in Fabry disease. Clearly, although premature atherosclerosis is suggested to occur, most studies describe absence of characteristic plaque formation. Smooth muscle cell hypertrophy, is probably the earliest feature of a complex vasculopathy, as in females and atypical cardiac variants, who have residual enzyme activity, no endothelial storage of significance is found. Subsequently, processes occur as observed in neo intima formation however with formation of more fibrotic structures. In the presence of a hyperdynamic circulation in combination with a less compliant vascular wall, it is hypothesized that upregulation of local renin angiotensine systems may occur. Angiotensin II is known to increase adhesion molecules, cytokines and chemokines and exerts a pro-inflammatory effect on leucocytes, endothelial cells and vascular smooth muscle cells. This enhances release of pro-thrombotic factors and opposes actions mediated through angiotensin 2 (AT2) receptor, including the release of nitric oxide (NO). A combination of reduced vascular compliance and activation of pro-thrombotic factors can lead to vascular complications in Fabry disease.

Can we use statins to prevent stroke in Fabry disease?

Fabry disease is a rare, X-linked lysosomal storage disease caused by an inborn deficiency of alpha-galactosidase A, which results in the progressive accumulation of globotriaosylceramide and other neutral glycolipids in a range of cells and tissues. In association with the renal and cardiac insufficiency, cerebrovascular complications can result in the death of the patients. Several mechanisms causing vascular damage that leads to the development of deep-white matter lesions have been described. Recent clinical trials strongly suggest that statins protect against stroke by neuroprotective properties or pleiotropic effects.

AIM

To evaluate evidence and potential beneficial effects of statins in the vasculopathy of Fabry disease.

Plasma markers of coagulation and endothelial activation in Fabry disease: impact of renal impairment

BACKGROUND

In Fabry disease, storage of globotriaosylceramide (Gb3) in arterial walls is one of the main pathogenetic factors that are thought to underlie the clinical manifestations of the disease. Abnormalities of the vessel wall, haemodynamics and pro- and anticoagulant factors may play a role, though the exact pathophysiology is incompletely understood. In this study, we try to clarify inconsistencies regarding coagulation activation, fibrinolysis, platelet activation and endothelial activation in 36 patients with Fabry disease.

METHODS

Cell-derived microparticles, markers for coagulation activation (F(1+2), TAT, sTF, sEPCR), fibrinolysis (D-dimer, tPA, alpha(2)-AP), platelet activation (beta-TG, PF4), endothelial activation (vWF) and acute phase response (IL-6, CRP) were studied in relation to renal function and severity of the disease and compared to data from 36 age- and sex-matched healthy controls (17 males).

RESULTS

Markers for endothelial activation and fibrinolysis were normal. Male patients had elevated levels of sTF and beta-TG, with an association between sTF and renal function and severity of the disease. In female patients, levels of TAT, beta-TG, PF4, CD63-positive platelet-derived microparticles and IL-6 were somewhat increased, with no correlation with renal function or disease severity.

CONCLUSIONS

Only minimal abnormalities in markers for platelet, endothelial activation and coagulation activation and fibrinolysis could be established in a large cohort of Fabry disease patients. The existing laboratory abnormalities are more likely related to renal insufficiency rather than to Fabry disease itself.

Middelheim Fabry Study (MiFaS): a retrospective Belgian study on the prevalence of Fabry disease in young patients with cryptogenic stroke

OBJECTIVE

To assess the prevalence of Fabry disease in young patients with cryptogenic stroke.

PATIENTS AND METHODS

We retrospectively assessed the prevalence of Fabry disease in patients aged 16-60 years that were admitted to ZNA Middelheim Hospital from January 1, 2000 to December 31, 2004 for cryptogenic stroke. We screened for Fabry disease by measurement of alpha-galactosidase A and beta-glucuronidase activity on blood spot. In all patients with abnormal enzymatic activity and in all female patients with low normal values, genetic sequencing of the alpha-GAL-gene was performed.

RESULTS

In a population of 103 young patients with cryptogenic stroke that met the in- and exclusion criteria, we were unable to identify any patient with Fabry disease.

CONCLUSION

Based on the results of alpha-galactosidase A and beta-glucuronidase activity, genetic sequencing and the low prevalence of clinical signs and symptoms of Fabry disease in this population, we believe that the true prevalence of Fabry disease in patients with cryptogenic stroke may be less than currently accepted in literature.