R Baker

Prevalence of Anderson–Fabry disease in patients with hypertrophic cardiomyopathy: the European Anderson–Fabry Disease Survey

Objectives The prevalence of Anderson–Fabry disease (AFD) in patients presenting with unexplained left ventricular hypertrophy (LVH) is controversial. The aim of this study was to determine the prevalence of AFD in a large, consecutive cohort of patients with hypertrophic cardiomyopathy (HCM) using rapid mutation screening. Design, Setting and Patients A European multicentre cross-sectional study involving 13 referral centres. Inclusion criteria for the study were: men aged at least 35 years and women aged at least 40 years with unexplained LVH (maximum left ventricular wall thickness ≥1.5 cm). All patients were screened using a denaturing high-performance liquid chromatography protocol for rapid mutation screening of the α-galactosidase A (α-Gal A) gene and, if a sequence variant was found, direct sequencing was performed. 1386 patients (63.9% men, mean age 57.9±12.0 years) were enrolled in the study. Results Seven (0.5%) patients (age 57.4±9.0 years (45–72); three (43%) men) had pathogenic α-galactosidase A mutations. Polymorphisms were identified in 283 patients (20.4%). Maximal left ventricular wall thickness in patients carrying a disease-causing mutation was 18±2 mm (range 15–22); four patients had concentric LVH and the remainder had asymmetric septal hypertrophy. Conclusions The prevalence of AFD gene mutations in a large, consecutive cohort of European patients with unexplained LVH is 0.5%.

Belgian Fabry Study Prevalence of Fabry Disease in a Cohort of 1000 Young Patients With Cerebrovascular Disease

Background and Purpose— Data on the prevalence of Fabry disease in patients with central nervous system pathology are limited and controversial. In this study, we assessed the prevalence of Fabry disease in young patients presenting with cerebrovascular disease in Belgium. Methods— In this national, prospective, multicenter study, we screened for Fabry disease in 1000 patients presenting with ischemic stroke, transient ischemic attack, or intracranial hemorrhage; unexplained white matter lesions; or vertebrobasilar dolichoectasia. In male patients, we measured &agr;-galactosidase A (&agr;-GAL A) activity in dried blood spots. Female patients were screened for mutations by exonic DNA sequencing of the &agr;-GAL A gene. Results— &agr;-GAL A activity was deficient in 19 men (3.5%), although all had normal &agr;-GAL A gene sequences. Enzymatic deficiency was confirmed on repeat assessment in 2 male patients (0.4%). We identified missense mutations in 8 unrelated female patients (1.8%): Asp313Tyr (n=5), Ala143Thr (n=2), and Ser126Gly (n=1). The pathogenicity of the 2 former missense mutations is controversial. Ser126Gly is a novel mutation that can be linked to late-onset Fabry disease. Conclusion— &agr;-GAL A deficiency may play a role in up to 1% of young patients presenting with cerebrovascular disease. These findings suggest that atypical variants of Fabry disease with late-onset cerebrovascular disease exist, although the clinical relevance is unclear in all cases.

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.

Local Regulation of Glucocorticoid Activity in Sites of Inflammation: Insights from the Study of Tuberculosis

Abstract: In sites of inflammation there is a change in the equilibrium between the enzymes that inactivate cortisol by conversion to cortisone and those that reactivate cortisone by conversion to cortisol. Current evidence suggests that during an immune response with a Type 1 cytokine profile such as tuberculosis, there is locally enhanced reductase activity with locally increased cortisol concentrations due to recruitment of cortisone. This results in enhanced cortisol mediated feedback on the inflammatory process, and deviation of the response towards Type 2. Preliminary data suggest that eventually, in the presence of Type 2 cytokine polarization, the enzyme equilibrium may reverse again and cortisol is then locally inactivated to cortisone. Together with changes in glucocorticoid receptor expression and function this may result in local cortisol resistance and susceptibility to tissue damage mediated by proinflammatory cytokines. These observations help to explain the sequence of events in several infectious, inflammatory and autoimmune diseases.

Cytotoxic drugs enhance the ex vivo sensitivity of malignant cells from a subset of acute myeloid leukaemia patients to apoptosis induction by tumour necrosis factor receptor-related apoptosis-inducing ligand

Summary. We have studied the actions of tumour‐necrosis‐factor‐related apoptosis‐inducing ligand (TRAIL) on cells isolated from patients with acute myeloid leukaemia (AML). Apoptosis induction was initially assessed by quantitative morphological analysis. Only 2/19 isolates showed a > 10% increase in apoptotic cells following TRAIL treatment. However, incubation with TRAIL combined with fludarabine, cytosine arabinoside or daunorubicin resulted in additive or super‐additive apoptosis induction in approximately half of the isolates. Molecular evidence of super‐additive apoptosis induction by TRAIL and cytotoxic agents was obtained by quantification of caspase 3 activation, detected by Western blot analysis of poly (ADP ribose) polymerase cleavage. The ability of TRAIL and daunorubicin to induce super‐additive apoptosis correlated with the ability of these agents to activate caspase 8 and to augment cellular levels of the truncated pro‐apoptotic form of the BCL‐2 family member BID. Our data suggest that co‐administration of TRAIL with conventional cytotoxic drugs may be of therapeutic value in some patients with AML.

Enhanced differentiation of osteoclasts from mononuclear precursors in patients with Gaucher disease.

Gaucher disease (GD) is an autosomal recessive disorder caused by deficiency of β-glucocerebrosidase. Storage of glucosylceramide in reticuloendothelial cells results in multiorgan pathology including bone disease. Established skeletal disease may remain problematic despite Gaucher-specific treatment. Both osteopenia and osteonecrosis have been described but the underlying pathophysiology, in particular the role of monocyte-derived osteoclasts is not well defined. The objective of this study was to explore the effect of glucocerebrosidase deficiency, inhibition and replacement on osteoclast development and function. In cultures derived from GD patients, or where GBA was chemically inhibited multinucleate giant cells expressing markers of osteoclast differentiation occurred earlier and in greater numbers compared to normal controls and the functional capacity of osteoclasts for bone resorption was enhanced. Increases in osteoclast number and activity correlated with radiological markers of active bone disease. Abnormalities were reversed by addition of specific therapies and were attenuated by co-culture with cells derived from healthy controls (HCs). Numbers of osteoblast lineage cells in the peripheral blood were mismatched to osteoclast precursors indicating uncoupling of osteoblast-osteoclast regulation which may further impact on bone remodelling. Elucidation of the underlying mechanisms of these changes will suggest rational therapies for the most disabling aspect of this condition.

Phenotypical characterization of α-galactosidase A gene mutations identified in a large Fabry disease screening program in stroke in the young

OBJECTIVE In the Belgian Fabry Study (BeFaS), the prevalence of Fabry disease was assessed in 1000 young patients presenting with stroke, unexplained white matter lesions or vertebrobasilar dolichoectasia. The results of the BeFaS suggested that Fabry disease may play a role in up to 1% of young patients presenting with cerebrovascular disease. However, the clinical relevance was unclear in all cases. We report on detailed phenotyping in subjects identified with α-galactosidase A (α-Gal A) enzyme deficiency or GLA mutations identified in the BeFaS (n=10), and on the results of family screening in this population. METHODS Family screening was performed to identify additional mutation carriers. Biochemical and/or clinical evaluation of all subjects (BeFaS index patients and relatives carrying a GLA mutation) was performed. RESULTS Genetic family screening revealed 18 additional GLA mutation carriers. Bloodspot α-Gal A enzyme activity was normal in all GLA mutation carriers, even in 2 males with the p.A143T mutation. Plasma Gb3 and lyso-Gb3 levels were normal in all subjects. Elevated Gb3 in urine was detected in 2 subjects. Some classic clinical signs of Fabry disease, like angiokeratoma or cornea verticillata, could not be detected in our population. Cardiac symptoms of Fabry disease were found in 6 out of 10 p.A143T carriers. No signs of cerebrovascular disease were found in the relatives with a GLA mutation. CONCLUSIONS We could not identify mutations causing the classical clinical phenotype of Fabry disease in our cerebrovascular disease population. Enzyme activity analysis in bloodspots and plasma may fail to identify late-onset variants of Fabry disease. We recommend genetic testing when an atypical, late-onset variant of Fabry disease is suspected in a male cerebrovascular disease patient. However, this may lead to the identification of non-disease causing or controversial genetic variants.

Cortisol metabolism, cortisol sensitivity and the pathogenesis of leprosy reactions

Summary The concentration of cortisol in a tissue is regulated by a reversible enzyme ‘shuttle’ that can deactivate cortisol by converting it to cortisone, or activate cortisone by converting it to cortisol. The activity of this shuttle, and the direction in which it operates, is regulated by numerous factors including cytokines. This results in large swings in the effective cortisol concentration in sites of inflammation at different phases of an inflammatory response. Thus changes in local cortisol concentration can be largely independent of circulating cortisol levels. The relevant shuttle enzymes are present in skin, blood vessels and nervous tissue, and inhibition of the enzymes in skin enhances the local anti‐inflammatory effect of cortisol. We therefore suggest that changes in the activity or direction of action of the shuttle in leprosy lesions may predispose to reactions, requiring exogenous steroid supplements to regain control of the inflammation.

Patients with Gaucher disease living in England show a high prevalence of vitamin D insufficiency with correlation to osteodensitometry.

AIM Gaucher disease type 1 (GD-1) is the most prevalent lysosomal storage disorder and frequently causes osteopenia and osteoporosis. Adequate vitamin D levels are essential for bone health. The present study retrospectively analyzed 25-hydroxyvitamin D (25[OH]D) in outpatients with GD-1. PATIENTS AND METHODS Sixty GD-1 patients living at home and with residence in southern or central England (34 men, 26 women), aged 17-85 years (mean 45.0 years) were seen at routine follow-up visits (range: 1-9, mean: 4.4) between January 2003 and July 2007. Overall, 264 blood samples, collected at different seasons of the year, were present for laboratory testing. The retrospective interpretation of vitamin D deficiency was based on different cut-off levels of 25(OH)D (<25 nmol/L, <50 nmol/L, <80 nmol/L) and the seasons of the year. Vitamin D sufficiency was defined as 25(OH)D >80 nmol/L. RESULTS The mean+/-SD of 25(OH)D was 58.2+/-30.3. Degrees of vitamin D deficiency (<25 nmol/L, <50 nmol/L, <80 nmol/L) were present in 9.1%, 44.3%, 83.0%, vitamin D sufficiency (>80 nmol/L) in only 17.0%, respectively. A significant seasonal variation of 25(OH)D was present. Results of vitamin D deficiency for December-May were 15.7%, 63.8%, 92.9%, and for June-November 2.9%, 26.3%, 73.7%. The 25(OH)D values representing the seasonal nadir observed during the season December-May showed a significant correlation with T-scores and Z-scores of the lumbar spine and hip. Parathyroid hormone and 25(OH)D were inversely correlated. CONCLUSIONS Vitamin D deficiency is frequent among GD-1 patients. To optimize treatment of GD-1 vitamin D supplementation should be recommended.

Human and murine tuberculosis as models for immuno-endocrine interactions

Recent studies of human and murine tuberculosis have revealed striking changes in adrenal steroid output and metabolism. In this review we use tuberculosis as a model on which to base discussion of the ways in which these changes, even when not disease-specific, may impact upon the function of T lymphocytes during chronic inflammation. Other chapters in this volume amplify further several of the topics highlighted in this one.