T1 mapping in patients with Fabry disease predicts functional and morphological abnormalities in cardiac MRI

Introduction

About 50% of Fabry disease (FD) patients develop cardiac manifestation, also known as Fabry cardiomyopathy. Beside echocardiography, cardiac magnetic resonance imaging (CMR) is included in the regular assessment of these patients, allowing non-invasive tissue characterization via T1 Mapping but also evaluation of morphological and functional characteristics.

Purpose

Myocardial strain measured by feature-tracking CMR has been previously shown to be a sensitive indicator of mechanical dysfunction in different diseases. We therefore evaluated changes of these parameters over the time, potentially reflecting disease progression in patients with FD. Furthermore, we also assessed the association of T1 mapping with follow-up changes of myocardial strain. Thus, our data may provide novel insights about cardiac changes in the natural course of the disease and cardiac effects of specific therapies.

Methods

We used post processing software for CMR to analyze baseline and follow-up cardiac involvement in a cohort of FD patients who were enrolled in the KarMA study, which examines cardiac changes over time. We measured left ventricular mass (LVM), left ventricular end-systolic and end-diastolic volume (LVEDV, LVESV), left ventricular ejection fraction (LVEF), mean left ventricular T1 relaxation times (T1), global longitudinal strain (GLS), global regional strain (GRS) and global circumferential strain (GCS). Statistical analyses included T-test and Spearman's correlation.

Results

CMR Images of 33 Patients were analyzed (22 females; mean age 40.8±16.3 years; at baseline 17 were therapy naïve and 16 on ERT), of whom 31 underwent a second CMR. In 18 patients (10 females; 44.9±16.0 years) myocardial strain measurement by feature-tracking was possible in both examinations. T1, LVM, LVEDV and LVESV, LVEF as well as GLS, GRS and GCS showed no significant change during the mean follow-up period of 43 (±17) months in all patients. However, we found a significant correlation of baseline T1 (967±84.5ms) with follow up values of LVM (84.9±32.7 g/m2; p=0.02, ρ=−0.462), LVEDV (63.0±17.6 g/m2 p=0.049 ρ=−0.398) and GRS (70.2±14.2% p=0.011 ρ=−0.5). Baseline T1 also correlated with changes in LVM (p=0.036 ρ=−0.44) and changes of GCS (p=0.001 ρ=−0.858) from baseline to follow up. Differences in T1 from baseline to follow up correlated with follow-up values of GLS (−19.5±3.57 p=0.044, ρ=−0.414) and GRS (69.1±18.7 p=0.003, ρ=−0.588).

Conclusion

T1, reflecting glycosphingolipid accumulation might predict changes in LVM, LVEDV and strain. Moreover, changes in T1, reflecting myocardial remodeling, go in parallel with worse left ventricular function shown by more positive values of GLS, GCS and GRS. T1 mapping together with strain parameters are important markers for monitoring patients with FD.

Funding Acknowledgement

Type of funding source: None

P1832 T1 mapping and echo-global longitudinal strain are early markers of cardiac involvement in patients with fabry disease

OnBehalf

Constantin Gatterer

Introduction

Fabry disease (FD) is one of the most common lysosomal storage diseases caused by deficiency of Alpha-Galactosidase A and accumulation of glycosphingolipids in all cells containing lysosomes. Cardiac involvement is characterized by left ventricular hypertrophy, conduction abnormalities and myocardial fibrosis with consecutive cardiomyopathy in late stages.

Purpose

As the detection of early signs of cardiac involvement is crucial for the initiation of enzyme replacement therapy (ERT) or Chaperon therapy, we intended to find early imaging markers.

Methods

Cardiac MRI (CMR) including Late Gadolinium Enhancement (LGE), representing fibrosis, and T1-mapping as well as echocardiography with measurement of global longitudinal strain (GLS) were done as part of the regular check-ups for patients with FD.

Results

The study cohort of 30 FD patients (20-69 years, 53% women) in different stages of disease showed low GLS values already at the time of baseline echocardiography (mean: -17,22%), correlating with the amount of LGE (r = 0,73; p = 0,003) and ejection fraction measured by CMR (CMR-EF; r=-0,74; p = 0,002).

After an average follow-up of 39 months (STD 18), GLS values were significantly declined (-15,51 %; p = 0,009) and correlated with T1 times (r = 0,7; p = 0,04), while LGE and CMR-EF did not significantly change compared to baseline.

Baseline T1 times correlated negatively with the reduction of GLS (r=-0,7; p = 0,003), while LGE and CMR-EF showed no correlation with the course of GLS. ERT appeared to have no influence on the extend of GLS reduction.

Conclusion

Low native CMR T1 times, indicating sphingolipid accumulation in the myocardium, seem to represent the beginning of cardiac involvement in FD and might predict the course of GLS. GLS is a sensitive parameter for early detection of cardiac manifestation and disease progression, while LGE and CMR-EF could not recognize slight deterioration of left ventricular function.

A Controlled Study of Sorbent Suspension Dialysis in Chronic Liver Disease and Hepatic Encephalopathy

To investigate the role of extracorporeal detoxification in cirrhotic patients with advanced hepatic encephalopathy not responding to medical treatment, 20 patients were randomized to receive six hours of additional sorbent dialysis or ongoing standardized medical treatment. Following treatment, the clinical stage of encephalopathy remained unchanged in both groups. Abnormal sensory evoked potentials improved following sorbent dialysis (N70 latency, 128 ms before versus 110 ms after treatment, P<0,05; cervico-cranial transmission, 7.7 ms versus 6.8 ms, P<0.01) indicating improvement in important aspects of cerebral function. In contrast, brain function remained unchanged following medical treatment (N70 latency, 114 ms versus 113 ms; cervico-cranial transmission, 7.7 ms versus 7.2 ms, P=NS, respectively). Serum benzodiazepine levels decreased significantly after sorbent dialysis but not after medical treatment. Biocompatibility of sorbent dialysis was limited and clinical complications occurred in a proportion of patients. In conclusion, a six-hour treatment with sorbent suspension dialysis did not ameliorate the clinical stage of HE but improved neurophysiologic function in cirrhotic patients who had not responded to conventional medical treatment.

Polyetiology of Renal Allograft Dysfunction

In 101 consecutive patients with renal allograft dysfunction a correlation of Duplex Doppler sonography (DDS) with histopathologic reports of simultaneously performed biopsies was made. Renal vascular impedance was estimated by calculating the resistive index (RI). A total of 290 different specific histologic diagnoses (mean 2.1 ± 0.84 diagnoses/biopsy) was noted. With increasing time interval to transplantation, single diagnoses as cause of allograft dysfunction decreased. DDS could not reliably differentiate, exclude, or grade any of the common causes of renal allograft dysfunction like vascular and/or cellular rejection, chronic rejection, acute tubular necrosis, cyclosporin nephrotoxicity, relapse of glomerulonephritis and infection. Follow-up studies after established histologic diagnosis in 19 patients with persisting allograft dysfunction demonstrated a lack of sensitivity of DDS to significant superimposed causes of transplant malfunction. We conclude that biopsy is still necessary to direct proper therapy of renal allograft dysfunction.

[Thrombotic microangiopathy : Relevant new aspects for intensive care physicians]

Die thrombotische Mikroangiopathie (TMA) ist klinisch durch eine mechanische Hämolyse, eine geringradig bis stark ausgeprägte Thrombopenie und ein akutes Nierenversagen charakterisiert. Differenzialdiagnostisch kommen das atypische hämolytisch-urämische Syndrom (aHUS), die thrombotisch-thrombozytopenische Purpura (TTP), das Shiga-Toxin-assoziierte HUS (STEC-HUS, früher typisches HUS), und andere seltene Formen der TMA infrage. Ferner kann im Rahmen von diversen Autoimmunerkrankungen, maligner Hypertonie, Malignomen und Infektionen eine TMA als sekundäres Phänomen entstehen. Pathophysiologisch kommt es beim aHUS zu einer überschießenden Aktivierung des alternativen Wegs des Komplementsystems. Essenziell ist daher eine rasche Klärung der zugrunde liegenden Ursache der TMA und eine entsprechende Therapie der Grundkrankheit bei den wesentlich häufigeren sekundären TMA. Bei der TTP ist eine rasche Initiierung von Plasmainfusionen bzw. Plasmaaustausch unumgänglich. Für komplement-mediierte Formen bestehen als etablierte Therapie der Plasmaaustausch und als moderne sehr erfolgreiche Therapieoption Antikomplementtherapien.

Enzyme replacement therapy with agalsidase alfa in patients with Fabry's disease: an analysis of registry data

BACKGROUND

We analysed 5-year treatment with agalsidase alfa enzyme replacement therapy in patients with Fabry's disease who were enrolled in the Fabry Outcome Survey observational database (FOS).

METHODS

Baseline and 5-year data were available for up to 181 adults (126 men) in FOS. Serial data for cardiac mass and function, renal function, pain, and quality of life were assessed. Safety and sensitivity analyses were done in patients with baseline and at least one relevant follow-up measurement during the 5 years (n=555 and n=475, respectively).

FINDINGS

In patients with baseline cardiac hypertrophy, treatment resulted in a sustained reduction in left ventricular mass (LVM) index after 5 years (from 71.4 [SD 22.5] g/m(2.7) to 64.1 [18.7] g/m(2.7), p=0.0111) and a significant increase in midwall fractional shortening (MFS) from 14.3% (2.3) to 16.0% (3.8) after 3 years (p=0.02). In patients without baseline hypertrophy, LVM index and MFS remained stable. Mean yearly fall in estimated glomerular filtration rate versus baseline after 5 years of enzyme replacement therapy was -3.17 mL/min per 1.73 m(2) for men and -0.89 mL/min per 1.73 m(2) for women. Average pain, measured by Brief Pain Inventory score, improved significantly, from 3.7 (2.3) at baseline to 2.5 (2.4) after 5 years (p=0.0023). Quality of life, measured by deviation scores from normal EuroQol values, improved significantly, from -0.24 (0.3) at baseline to -0.17 (0.3) after 5 years (p=0.0483). Findings were confirmed by sensitivity analysis. No unexpected safety concerns were identified.

INTERPRETATION

By comparison with historical natural history data for patients with Fabry's disease who were not treated with enzyme replacement therapy, long-term treatment with agalsidase alfa leads to substantial and sustained clinical benefits.

FUNDING

Shire Human Genetic Therapies AB.

Cartilage biomarkers in hemodialysis patients and the effect of beta2-microglobulin on articular chondrocytes

OBJECTIVE

Dialysis-related amyloidosis (DRA) is a severe complication of maintenance hemodialysis (HD). Given the predominant deposition of beta(2)-microglobulin (beta2m) fibrils on articular cartilage in early DRA, we investigated the significance of beta2m and its relationship to distinct cartilage biomarkers in early DRA diagnosis in HD patients. Furthermore, we assessed the effects of beta2m on articular chondrocytes in vitro.

METHODS

Serum samples from 133 patients were collected before and after HD. Type II collagen cleavage product (C2C), procollagen II c-propeptide (CPII), aggrecan chondroitin sulfate 846 epitope (CS-486) and cartilage oligomeric matrix protein (COMP) levels were determined by enzyme-linked immunosorbent assay. Primary bovine articular chondrocytes were cultured as monolayers and incubated with beta2m at 1.5mg/l and 20mg/l. Cartilage glucosaminoglycan synthesis was measured by [(35)S]sulfate incorporation. mRNA expression of interleukin (IL)-1beta, matrix metalloproteinases (MMPs)-3 and -9 was measured by reverse-transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Incubation with beta2m at 20mg/l significantly decreased matrix biosynthesis. PCR analysis revealed an increase of IL-1beta, as well as MMPs-3 and -9 on the mRNA level. C2C/CPII, CS-486 and COMP levels were increased only in a subset of patients without a significant correlation with beta2m concentrations. A subgroup analysis elucidated an increase in type II collagen degradation during the first years of HD, as shown by the elevation of C2C/CPII ratio.

CONCLUSION

beta2m exerted anti-anabolic effects on articular chondrocytes in vitro and might be involved in cartilage degradation in HD patients. beta2m serum levels, however, did not reflect cartilage degradation in DRA. The assessment of C2C/CPII, CS-486 or COMP concentrations apparently has minor relevance in DRA diagnosis in HD patients. However, the increased type II collagen breakdown within 5 years after HD onset possibly mirrors the early stages of DRA. Thus, the C2C/CPII ratio could be employed in longitudinal studies, since it may reflect a risk for DRA related arthropathy development in a subset of patients.

Classification of chronic kidney disease by estimated glomerular filtration rate

BACKGROUND

Serum creatinine concentration alone as a marker of kidney function is inadequate. Thus several equations for estimating glomerular filtration rate (eGFR) have been proposed within the last years.

PATIENTS AND METHODS

In our study we compared three frequently used equations, the abbreviated modification of diet in renal disease (MDRD) formula, the extended MDRD formula and the recently proposed Mayo clinic equation in a large patient cohort.

RESULTS

A total of 244 507 patients attending the Vienna General Hospital were evaluated for their kidney function and three equations for eGFR were compared. The median age of the patients was 51 years (ranging from 18.0 to 102.6 years) with 44.3% males (n = 108 527). We observed a significant increase of patients with eGFR classes four and five (according to Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines) with advanced age. Whereas approximately 1% of patients < 30 years presented with eGFR classes four and five (defined as eGFR < 30 mL min(-1) 1.73 m(-2)), this prevalence increased up to approximately 12% in patients at the age of 80 years or older. All three equations showed comparable results for eGFR classes four and five. The proportion of patients with mild to moderate impairment of kidney function is higher using both MDRD equations.

CONCLUSIONS

The MDRD equations (particularly the abbreviated MDRD formula) result in considerably higher rates of eGFR classes two and three compared to the Mayo Clinic equation, while all three were comparable in classes four and five. This should be considered when eGFR is used in the diagnosis of chronic kidney disease.

Low-turnover bone disease in hypercalcemic hyperparathyroidism after kidney transplantation

Hypercalcemia in persistent secondary hyperparathyroidism after kidney transplantation is considered to result from increased bone resorption. Bone biopsies' studies, however, have never been performed in these patients. Bone biopsies after double tetracycline labeling were obtained from 17 patients with hypercalcemic hyperparathyroidism and an estimated glomerular filtration rate > 30 mL/min/1.73 m2. Serologic bone markers, calcitriol, intact fibroblast growth factor-23 (iFGF-23), and serum and 24h urine concentration of calcium and phosphate were measured in all patients. Tubular maximum for phosphate corrected for GFR (TmP/GFR), and the fractional excretion of calcium (FeCa) were calculated. High-turnover renal osteodystrophy (ROD) was present in nine and low-turnover ROD in eight patients. The bone formation rate was significantly associated with bone alkaline phosphatase, c-telopeptide and osteocalcin. In patients with high turnover ROD, osteocalcin was also significantly higher than in patients with decreased bone formation. The FeCa was normal or below normal in 14/17 patients. TmP/GFR was below normal in all patients. Neither intact PTH nor iFGF-23 was associated with TmP/GFR, FeCa or any histomorphometric bone parameter. We conclude that hypercalcemia of posttransplant hyperparathyroidism can be associated with high or low turnover bone disease. Decreased calcium excretion suggests an additive tubular effect on hypercalcemia.

[Fabry disease: demographic data since introduction of enzyme replacement therapy]

BACKGROUND AND OBJECTIVE

Fabry's disease is a rare, X-chromosome linked recessive lysosomal storage disorder. In its course multiple organ damage occurs, e.g. in skin, nerves, kidneys and heart. The disease not only markedly impairs the quality of life but also shortens life expectancy if untreated. As it is a rare and not widely known disease with considerable variability of its symptoms it is often not or only belatedly diagnosed. Since 2001, enzyme replacement has become available as an option in the causal treatment. It was the aim of this study to analyse the demography and clinical expression of the disease.

PATIENTS AND METHODS

Data were obtained from the Fabry Outcome Survey (FOS), a Europe-wide data bank for the documentation of the disease's clinical course, on 262 patients (130 males, 132 females; mean age 37.5 and 34 years, respectively on entry in the FOS) in Germany, Switzerland and Austria.

RESULTS

Typical symptoms - acroparesthesias, joint pain, hypohidrosis, fever and angiokeratoma - have their onset in childhood (mean age nine years). Symptoms start significantly earlier in males than females. The interval between onset of the first symptoms and establishment of the diagnosis is about 15 years. The severity of the clinical picture, as measured in the POS Mainz severity score index (MSSI), correlates significantly with the person's age (p = 0.0001). Main causes of morbidity and death in Fabry's disease are involvement of the kidneys or heart, the one or other occurring in 75% of patients. 171 patients (38 [65.3%]: 92 males, 79 females) are at present being continually treated with enzyme-replacement (ERT), agalsidase-a, i.e. 70.8% of all male and 59.8 of all female patients in the FOS.

CONCLUSIONS

It is of great importance for the prognosis and quality that Fabry's disease is diagnosed as early as possible and treated adequately before the onset of organ damage. If the listed symptoms by themselves remain unexplained, Fabry's disease should be considered in the differential diagnosis. National and international observational studies, such as the FOS, significantly contribute to gaining important clinical data on this heterogeneous disease.

Anemia in patients with Wegener's granulomatosis

AIMS

Anemia is commonly observed among patients with chronic kidney disease (CKD). No such information is available for patients with a history of systemic vasculitis.

METHODS

We examined the prevalence of anemia, the response to therapy with erythropoiesis-stimulating agents (ESA), and the association of anemia with the kidney function in clinically stable patients with Wegener's granulomatosis in a retrospective, single-center study.

RESULTS

The mean hemoglobin concentration of 36 patients (mean age: 58 years; 15 female, 21 male; mean duration of disease: 4.6 years) was 13.0+/-2.1 g/dl, and the mean estimated glomerular filtration rate (eGFR) was 41+/-21 ml/min/1.73 m(2). 14 of 36 patients (38.8%) presented with anemia (hemoglobin concentration < 12 g/dl in women, < 13 g/dl in men, or ESA therapy). In patients with a CKD Stage 3 or 4, anemia was present about twice as much as compared to the Third National Health and Nutrition Examination Survey (NHANES III) population. The hemoglobin concentration, however, was not associated with a change of kidney function (p = 0.1578).

CONCLUSIONS

We found a higher prevalence of anemia in patients with Wegener's granulomatosis, as compared to the NHANES III population. The hemoglobin concentrations showed no association with changes of kidney function.

Calcitonin concentrations in patients with chronic kidney disease and medullary thyroid carcinoma or c-cell hyperplasia

It is currently not known which level of pentagastrin-stimulated calcitonin serum concentration indicates medullary thyroid carcinoma in patients with chronic kidney disease (CKD). We examined CKD stage 3-5 patients who had total thyroidectomy because of a pentagastrin-stimulated calcitonin concentration greater than 100 pg/ml, and tested the diagnostic performance of basal and pentagastrin-stimulated calcitonin levels for differentiating medullary thyroid carcinoma and C-cell hyperplasia in this patient population. A total of 180 CKD patients presented with an elevated calcitonin level and had a pentagastrin stimulation test. Forty patients showed a maximum pentagastrin-stimulated calcitonin concentration greater than 100 pg/ml, and 22 patients had a total thyroidectomy. Seven of these 22 patients presented with a medullary thyroid carcinoma, all other patients showed C-cell hyperplasia. Patients with medullary thyroid carcinoma showed higher unstimulated (212 pg/ml (36-577) vs 42 pg/ml (17-150); P < 0.001) and higher maximum pentagastrin-stimulated calcitonin concentrations (862 pg/ml (431-2423) vs 141 pg/ml (102-471); P < 0.001) as compared to patients with C-cell hyperplasia. The sensitivity (100%) and specificity (93%) estimates suggested that a maximum pentagastrin-stimulated calcitonin concentration greater than 400 pg/ml indicates the presence of medullary thyroid carcinoma in patients with CKD. Receiver-operating characteristic (ROC) analysis revealed an area under the ROC plot of 0.99 for maximum pentagastrin-stimulated calcitonin concentrations. A maximum pentagastrin-stimulated calcitonin concentration greater than 400 pg/ml appears to be a clinically meaningful threshold for thyroidectomy.

Metabolic alkalosis in a hemodialysis patient – successful treatment with a proton pump inhibitor

Hemodialysis patients develop metabolic acidosis due to their impaired excretion of daily produced protons (H+). The following report will show a rare case of severe metabolic alkalosis (predialysis pH 7.52, base excess (BE) +17) in a hemodialysis woman caused by self-provoked upper gastrointestinal H+ losses based on an eating disorder. Treatment with a proton pump inhibitor resulted in the normalization of acid/base homeostasis (predialysis pH 7.40, BE +1.6).

Hearing loss in Fabry disease: data from the Fabry Outcome Survey

Hearing loss is a common symptom in Fabry disease, but neither its natural course nor its aetiology has been defined precisely. The aim of this study was to provide a detailed epidemiological description of hearing impairment in patients in the Fabry Outcome Survey (FOS), which is the largest available database of Fabry patients. Questionnaires were completed by 566 Fabry patients, of whom 316 reported ear-related symptoms. Pure-tone audiograms from 86 patients, performed before starting enzyme replacement therapy, were analysed and compared with age- and sex-specific normal values (International Organization for Standardization, ISO 7029). When compared to an age-matched population (ISO 7029), 74% of patients had a threshold elevated above the 95th centile in at least one tested frequency. All frequencies were affected to a similar degree. However, only 14 patients (16%) were clinically affected by hearing impairment according to the age-independent World Health Organization (WHO) classification (mean threshold at 0.5, 1 and 2 kHz worse than 25 dB). Hearing loss was sensorineural in 63 patients (73%) of whom 7 patients (8%) had also a conductive component. One patient had a purely conductive hearing loss. Episodes of sudden hearing loss seemed to occur more frequently than in the general population. Men were affected earlier and more severely than women. Hearing in Fabry disease is significantly worse than in an age-matched general population but leads to clinically relevant hearing impairment in only 16% of cases. It resembles accelerated presbycusis with an additional Fabry-specific strial-type hearing loss.

Hyperhidrosis: a new and often early symptom in Fabry disease. International experience and data from the Fabry Outcome Survey

Hypohidrosis is a classic feature of Fabry disease; in contrast, hyperhidrosis has only been rarely described. The aim of the study is to characterise the baseline descriptive data on hyperhidrosis (frequency, age at onset, sex ratio and outcome with and without enzyme replacement therapy) in hemizygous male and heterozygous female patients with Fabry disease. We describe case histories of five patients with Fabry disease and hyperhidrosis seen at three different centres. We have also analysed a cohort of 21 paediatric patients in the UK and a large European cohort of patients enrolled in the Fabry Outcome Survey (FOS). Five patients (three female, two male) with hyperhidrosis were originally identified, although each had additional symptoms related to Fabry disease. The age at onset of hyperhidrosis was less than 18 years in four cases. In the cohort of 21 paediatric patients (12 female, nine male), one female had hyperhidrosis; the age at onset of this symptom was 11 years. In the FOS cohort, 66 of 714 patients with Fabry disease had hyperhidrosis (44 of 369 females, 11.9%; 22 of 345 males, 6.4%). The female predominance was observed in seven of nine countries from which data were analysed. Hyperhidrosis is an increasingly recognised feature of the Fabry disease phenotype. It is more prevalent in females than in males and often appears in childhood or adolescence. The efficacy of enzyme replacement therapy on this recently recognised symptom should be assessed.

Agalsidase alpha and hearing in Fabry disease: data from the Fabry Outcome Survey

Fabry disease is an X-linked lysosomal storage disorder characterized by multi-organ dysfunction, including hearing loss - mainly sensorineural. The recent introduction of enzyme replacement therapy (ERT) has resulted in improvements in renal and cardiac function, pain and quality of life. One study has also suggested small improvements in high-frequency hearing. In this paper, we study the effect of ERT on hearing in patients in the Europe-wide database - the Fabry Outcome Survey (FOS). Twenty-six patients in FOS had pure-tone audiometry performed up to 6 months before starting ERT with agalsidase alpha and after a median of 12 months of treatment. We assessed changes in hearing thresholds, expressed as deviations from the 50th centile of the normal population (International Organization for Standardization ISO 7029) to correct for age-related non-specific hearing deterioration. Hearing did not change significantly in ears with normal hearing (less than 10 dB deviation from the 50th centile of ISO 7029) or those with severe hearing loss (more than 40 dB deviation from the 50th centile of ISO 7029) at baseline. In ears with a mild or moderate hearing loss at baseline, hearing thresholds, expressed as deviations from the normal 50th centile, improved significantly by 4-7 dB at most frequencies (P < 0.05). Agalsidase alpha stabilizes, and possibly improves, hearing in Fabry patients who have not already progressed to severe hearing loss. Further follow-up of these patients will determine the longer-term effects of ERT.

Enzyme replacement therapy and renal function in 201 patients with Fabry disease

AIM

Fabry disease is a rare lysosomal storage disorder caused by deficient activity of alpha-galactosidase A, resulting in progressive cellular accumulation of glycolipids, which may ultimately result in endstage renal disease. We examined the effects of enzyme replacement therapy (ERT) with Agalsidase-alpha on renal function using data from a large international database, the Fabry Outcome Survey (FOS).

METHODS

This analysis was based on 1,040 serum creatinine measurements in 201 patients with Fabry disease, aged 20 - 60 years, with serum creatinine concentrations of less than 2 mg/dl and duration of ERT of up to 4.7 years. Both pretreatment and treatment data were used to examine independent predictors of changes in serum creatinine. In a second approach longitudinal serum creatinine measurements from 1 year before treatment, at baseline and 1 and 2 years after the start of treatment were analyzed in 20 patients with chronic kidney disease (CKD) Stage 2 and 3.

RESULTS

We found an independent negative association between serum creatinine and time on Agalsidase-alpha treatment (p < 0.05). Renal function declined significantly (p < 0.05) in the year before treatment. After 1 year of treatment, however, the decline in estimated glomerular filtration rate had been halted, and renal function was preserved for up to 2 years.

CONCLUSIONS

In conclusion, ERT with Agalsidase-alpha is associated with decrease of serum creatinine and may prevent the deterioration of renal function in patients with Fabry disease.

Intravenous iron therapy: well-tolerated, yet not harmless

In the majority of patients with chronic renal failure, it is essential to substitute erythropoietic agents and iron to maintain a haemoglobin level above 11 g dL-1. Intravenous iron is more effective than oral iron. Substitution of intravenous iron is mainly performed using iron(III)-hydroxide-sucrose complex (iron sucrose) and iron(III)-sodium-gluconate in sucrose (iron gluconate), and is, in general, well-tolerated. Nonetheless, intravenous iron therapy has effects on endothelial cells, polymorphonuclear leucocytes and cytokines which are most likely related to non-transferrin bound labile iron. These effects suggest a role of iron in infection or atherosclerosis. Yet, not all available data support the association of iron with infection and atherosclerosis. A recent trial showed that iron sucrose is safe when given as treatment for iron deficiency or for maintenance of iron stores. Nevertheless, iron therapy should be handled with caution but its use should not be feared whenever indicated.

Anaemia after renal transplantation

Anaemia is a frequent complication among long-term renal transplant recipients. A prevalence of approximately 40% has been reported in several studies. If renal function declines to stage 5 kidney disease, the prevalence of anaemia in kidney transplants is even higher. A positive correlation between haemoglobin concentration and creatinine clearance has been reported, which is a function of endogenous erythropoietin production by the functioning graft. Inflammation related to a retained kidney graft may cause hypo-responsiveness to erythropoietic agents once kidney transplant recipients return to dialysis. Furthermore, the use of azathioprine, mycophenolate mofetil and sirolimus may be associated with post-transplant anaemia. Along with erythropoietin deficiency, depletion of iron stores is one of the major reasons for anaemia in the kidney transplant population. The proportion of hypochromic red blood cells appears to be a useful parameter to measure iron supply and utilization as well as to estimate mortality risks in kidney transplant recipients. While anaemia is an important cardiovascular risk-factor after transplantation, our data suggest that anaemia is not associated with mortality and graft loss. Nevertheless, inadequate attention is paid so far to the management of anaemia after renal transplantation. A promising future aspect for risk reduction of cardiovascular disease includes the effect of erythropoietic agents on endothelial progenitor cells.

Hormonal profile and fertility in patients with Anderson-Fabry disease

Anderson-Fabry disease is a glycosphingolipid storage disorder with an X-linked recessive inheritance. The alpha-galactosidase A deficiency leads to a progressive accumulation of globotriaosylceramide in the endothelium and tissue cells of various organs. The kidney, heart and brain are predominantly affected. Reports on endocrine function and fertility rates in patients with Anderson-Fabry disease are sparse. In the present study, we assessed ovarian, testicular and adrenal function in a cohort of patients with Anderson-Fabry disease. Plasma follicle-stimulating hormone, luteinizing hormone, prolactin, estradiol, testosterone, sex hormone-binding globulin, somatotropin, insulin-like growth factor-I and serum cortisol were measured in 13 patients (six female and seven male), currently observed in an outpatient clinic. The profile revealed an undisturbed hormonal function and a normal fertility rate in both male and female Anderson-Fabry patients when compared with the corresponding Austrian population.

Measurement of renal function in patients with Fabry disease

Appropriate measurement of the glomerular filtration rate (GFR) is important for the assessment of renal function. This paper reviews the methods used to assess GFR in clinical trials of enzyme replacement therapy (ERT) in patients with Fabry disease, which include inulin clearance, 24-hour creatinine clearance, chromium ethylene diamine tetraacetate (51Cr-EDTA) clearance and cystatin C concentrations. GFR has also been estimated using calculations based on creatinine clearance (the Cockcroft-Gault formula) and the Modification of Diet in Renal Disease (MDRD) equation. Analysis of the results of these studies shows that there are striking discrepancies between estimated and measured GFR. For example, the MDRD equation overestimates GFR in patients with Fabry disease who have normal renal function. In addition, cystatin C has been shown to be of limited use for measuring renal function during ERT, because it is influenced by other factors such as age, gender and weight.

CONCLUSION

The use of exact methods, such as inulin clearance, 124I-iothalamate, 99mTc-DTPA, 51Cr-EDTA and iohexol, appears to be mandatory for a robust evaluation of the effects of ERT on GFR in patients with Fabry disease.

High prevalence of subclinical hypothyroidism in patients with Anderson-Fabry disease

Anderson-Fabry disease is a rare lysosomal storage disorder. It results from a deficiency of the lysosomal alpha-galactosidase A and leads to progressive accumulation of globotriaosylceramide in the endothelium and tissue cells of various organs. Some of the typical clinical findings such as tiredness, dry skin, myalgia and arthralgia as well as vague gastrointestinal complaints are also symptoms of hypothyroidism. Therefore, we studied the thyroid function in patients with Anderson-Fabry disease. Thyroid function was studied in 11 patients (6 female, 5 male) with Anderson-Fabry disease by measuring thyroid-stimulating hormone (TSH) and free thyroxine serum levels. Nine patients had chronic kidney disease with stage 1 and two with stage 5. Subclinical hypothyroidism (normal serum free thyroxine concentrations along with elevated serum TSH levels) was found in 4 of 11 patients (36.4%). Subclinical hypothyroidism was observed in both male and female patients as well as in patients with stage 1 and stage 5 kidney disease. Subclinical hypothyroidism is a common finding in patients with Anderson-Fabry disease, showing an excess prevalence as compared to the normal population. The high frequency seems to be relevant regarding the potential consequences of a hypothyroid state.

Fabry disease: overall effects of agalsidase alfa treatment

BACKGROUND

Fabry disease is a rare X-linked disorder caused by deficient activity of the lysosomal enzyme alpha-galactosidase A. Progressive accumulation of the substrate globotriaosylceramide in cells throughout the body leads to major organ failure and premature death. The Fabry Outcome Survey (FOS) is a European outcomes database which was established to collect data on the natural history of this little-known disease and to monitor the long-term efficacy and safety of enzyme replacement therapy (ERT) with agalsidase alfa. This paper presents the first analysis of the FOS database on the effects of ERT on renal function, heart size, pain and quality of life.

DESIGN

The effects of 1 and 2 years of ERT with agalsidase alfa on renal function (assessed by estimated glomerular filtration rate), heart size (assessed by echocardiography), pain (assessed by the Brief Pain Inventory) and quality of life (assessed by the European Quality of Life Questionnaire EQ-5D) were analyzed in a cohort of 545 patients, 314 of whom were receiving treatment (188 for at least 12 months and 92 for at least 24 months; mean duration of treatment, 17 months; maximum duration, 56 months).

RESULTS

Treatment with agalsidase alfa stabilized renal function in patients with a mild or moderate deterioration in renal function at baseline, reduced left ventricular size in patients who had an enlarged heart at baseline, and improved pain scores and quality of life. These improvements were similar in hemizygous men and heterozygous women with Fabry disease.

CONCLUSIONS

Enzyme replacement therapy with agalsidase alfa leads to significant clinical benefits in patients with Fabry disease, and treatment is likely to alter the natural history of this disorder.

Granulocyte function in patients with L-ferritin iron-responsive element (IRE) 39C-->T-positive hereditary hyperferritinaemia-cataract syndrome

BACKGROUND

Hereditary hyperferritinaemia-cataract syndrome (HHCS) is an autosomal dominant trait associated with mutations in the iron responsive element (IRE) of the ferritin light-chain (L-ferritin) gene. Patients typically show elevated serum ferritin concentrations without iron overload and a bilateral cataract. Hyperferritinaemia can be associated with granulocyte dysfunction in patients with thalassemia beta and in haemodialysis patients. The effect of increased L-ferritin levels on granulocyte function in patients with HHCS is unknown.

MATERIAL AND METHODS

We examined glucose uptake, oxidative burst, chemotaxis, phagocytosis, apoptosis and intracellular calcium concentrations in polymorphonuclear leucocytes (PMNLs) of five affected members of a family with HHCS and in five healthy individuals matched for age and gender.

RESULTS

Mutation testing revealed a 39C-->T transition in IRE in all five patients with HHCS. Serum ferritin levels of patients ranged between 907 and 2030 microg L(-1), respectively. In comparison with healthy individuals, PMNLs of patients with HHCS showed a significant increase in PMA-mediated stimulation of the oxidative burst, as well as a significantly higher stimulation of glucose uptake but no difference with respect to chemotaxis, phagocytosis, apoptosis and intracellular calcium concentrations.

CONCLUSION

In summary, our study suggests that hyperferritinaemia in patients with IRE 39C-->T-positive HHCS is associated with activation of PMNLs but not with disturbance of fundamental PMNL function.

Patterns of co-occurrence of three single nucleotide polymorphisms of the 5,10-methylenetetrahydrofolate reductase gene in kidney transplant recipients

BACKGROUND

Recently, a new mutation of the 5,10-methylenetetrahydrofolate reductase (MTHFR) encoding gene was first described (1793G > A). Only few reports have studied the prevalence of this polymorphism, especially in combination with other MTHFR mutations (677C > T, 1298A > C).

METHODS

We cross-sectionally identified the novel MTHFR 1793G > A polymorphism in 730 kidney transplant recipients. MTHFR 677C > T and 1298A > C were also assessed and the frequency of each was described individually as well as in cross-tabulation with the other MTHFR genotypes. The expected number of patients for each MTHFR genotype combination was calculated and contrasted with the observed numbers. Fisher's exact test was used for statistical inference.

RESULTS

The allelic frequency of MTHFR 1793G > A was 0.052. Seventy-two patients (9.9%) were heterozygous and two patients (0.3%) were homozygous. From the cross-tabulations, we identified 53 patients (expected: 33.6) with the MTHFR 1298AC/1793GA genotype and 17 patients (expected: 6.7) with the MTHFR 1298CC/1793GA genotype. Furthermore, we found two patients with double homozygosity for MTHFR 1793G > A and MTHFR 1298A > C (MTHFR 1793AA/1298CC genotype). The frequencies of these genotype combinations were substantially larger than could be expected (P < 0.001).

CONCLUSIONS

These findings suggest a selection or survival advantage for individuals with combined MTHFR 1793G > A and MTHFR 1298A > C genotypes, possibly owing to a mutually stabilizing effect on MTHFR enzyme activity.

A rare cause of anemia due to intestinal tuberculosis in a renal transplant recipient

A renal transplant recipient with stable allograft function presented with massive hemorrhagic diarrhea and severe anemia. No microbial infection could be found in stool cultures. Early colonoscopy showed severe colitis with ulceration. Histological samples confirmed granulomatous inflammation with acid-resistant Ziehl-Neelson-positive microorganisms of mycobacterial type. Polymerase chain reaction (PCR) analysis of native mucosal biopsies specified the infectious organism as Mycobacterium tuberculosis complex. The patient responded well to antimycobacterial therapy and was still asymptomatic after 6 months with a stable graft function. Our case shows that tuberculosis can be a severe clinical problem in transplant recipients. Most of the patients with intestinal tuberculosis, reported to literature, were diagnosed post mortem or after explorative laparotomy and bowel resection. Thus, intestinal tuberculosis should be considered when a transplant recipient shows abdominal symptoms with no clear evidence of another infection. Proper diagnosis and treatment resulted in a beneficial outcome in our patient.

The expanding clinical spectrum of Anderson-Fabry disease: a challenge to diagnosis in the novel era of enzyme replacement therapy

Anderson-Fabry disease is an X-linked recessive lysosomal storage disease resulting from deficient alpha-galactosidase A activity. The conception of the disease has changed within the last decade. Studies of the last years have shown that the disease is not limited to the classical full-blown manifestation in affected males, which is well known since more than a century, but may also occur in carrier females. The phenomenology may differ in severity and kind of organ manifestation. Cardiac and renal variants with solely disease manifestation of these organs have also been described in an increasing number. It is likely that a spectrum exists regarding alpha-galactosidase A activity in both genders on the one hand, and an additional one regarding the severity and the number of organs affected on the other. The purpose of this review is to sharpen physicians' perception of this disease. Early and accurate diagnosis is mandatory considering that this disorder is now, after introduction of the novel enzyme replacement therapy, a treatable disease.

Fabry disease defined: baseline clinical manifestations of 366 patients in the Fabry Outcome Survey

BACKGROUND

Fabry disease is a rare X-linked disorder caused by deficient activity of the lysosomal enzyme alpha-galactosidase A. Progressive accumulation of the substrate globotriaosylceramide in cells throughout the body leads to major organ failure and premature death. In response to the recent introduction of enzyme replacement therapy, the Fabry Outcome Survey (FOS) was established to pool data from European clinics on the natural history of this little-known disease and to monitor the long-term efficacy and safety of treatment. This paper presents the first analysis of the FOS database and provides essential baseline data against which the effects of enzyme replacement can be measured.

DESIGN

Baseline data from a cohort of 366 patients from 11 European countries were analysed in terms of demography and clinical manifestations of Fabry disease.

RESULTS

Misdiagnosis of Fabry disease is common, and the mean delay from onset of symptoms to correct diagnosis was 13.7 and 16.3 years in males and females, respectively. Although previously thought to have serious manifestations only in hemizygous men, the FOS database has confirmed that females heterozygous for Fabry disease are similarly affected. Furthermore, signs and symptoms of Fabry disease may be present from early childhood.

CONCLUSIONS

With the advent of enzyme replacement therapy, it is important that general practitioners and physicians in a range of specialties recognize the signs and symptoms of Fabry disease so that effective treatment can be given. Baseline data from FOS demonstrate that enzyme replacement therapy should not be restricted to hemizygous men, but should be considered for both heterozygous females and children.

Central venous catheter pinch-off and fracture: recognition, prevention and management

The so-called pinch-off syndrome is observed in up to 1% of all central venous catheters (CVCs), and is a valuable warning prior to fragmentation, which occurs in approximately 40% of the respective cases. As long-term indwelling CVCs are used with increasing frequency, this paper describes the necessity of pinch-off monitoring following the experiences of a case study and a review of the current literature on this specific topic in order to point out preventive practice guidelines. Besides easy preventive practices such as a high level of suspicion and adequate X-ray controls, findings give strong evidence that the most important specific factor might be the adequate approach. In our hands, the supraclavicular technique has provided the best results with regards to percutaneous introduction of large bore CVCs.

Long-term citrate anticoagulation for high-flux haemodialysis in a patient with heparin-induced thrombocytopenia type II

For the first time, long-term use of regional citrate anticoagulation for high-flux haemodialysis is reported in a patient with heparin-induced thrombocytopenia type II. A simple, flow-independent, citrate infusion protocol allowed efficient anticoagulation. Excellent solute removal, indicated by KT/V values of 1.52 to 1.98, was achieved. Electrolyte and acid-base balance as well as calcium homeostasis were well controlled over a period of 9 months.

Surface antigens of human mesangial cells: impact of growth surface or IL-1alpha

The interactions of mesangial cells (MC) with their environment are important events in glomerular physiology and pathology, yet a detailed characterization of the MC-surface antigens mediating these interactions is still lacking. In this study, a comparative phenotype analysis of primary human MC in culture using 191 monoclonal antibodies directed against 108 antigens was performed by flow-cytometry. The MC were grown on three different surfaces (human matrix, fibronectin, polystyrene) and cultured in the presence or absence of IL-1alpha. Seventy-one antibodies recognizing 35 different antigens (integrins: CD29, 49b, 49c, 49e, 51, 61; immunoglobulin gene family: CD54, 58, 90, 106, 146, 147, 166; growth factor receptors: CD105, 140b; apoptosis related: CD95; hemostatis related: CD141, 142; miscellaneous: CD44, 109, 138, 151, 157, 165, and 11 nonclustered antigens) reacted with mesangial cells. CD58, 109, 146, 147, 151, 157, 165, and 166 are reported for the first time to be present on human mesangial cells. In comparison to growth on polystyrene, CD44, 54, 95, 105, 109, 140b, 146, 147, 157, 165 and 166, were up-regulated on fibronectin, and CD44, 54, 90, 95, 105, 106, 109, 138, 140b, 141, 142, 146, 147, 151, 157, 165 and 166 were up-regulated on human matrix. The stimulation by IL-1alpha up-regulated CD44, 49e, 51, 54, 61, 106 on MC on polystyrene; CD49e, 51, 61, 106, 146, 165 on MC on fibronectin, and CD49e, 51, 54 on MC grown on human matrix. This analysis of surface antigen expression provides new information to enable a better understanding of the role of mesangial cells in glomerular pathophysiology.