The evaluation and treatment of gastrointestinal disease in children with cystinosis receiving cysteamine

Extrarenal complications of cystinosis

Cystinosis is a rare autosomal recessive disease with an incidence 1 per 100,000-200,000 live births. It is caused by pathogenic variants of the cystinosin (CTNS) gene that lead to impaired cystine transport from lysosomes to cystosol, resulting in cystine accumulation in lysosomes and subsequent cellular dysfunction. The initial manifestation, cystine accumulation in proximal tubular cells (PTCs), causes renal Fanconi syndrome, which presents with proximal renal tubular acidosis and generalized dysfunction of the proximal tubule, including the presence of polyuria, glycosuria, phosphaturia, aminoaciduria, tubular proteinuria, growth retardation, and rickets. Eventually, glomerular involvement, glomerular proteinuria, focal segmental glomerulosclerosis (FSGS), and progression to kidney failure occur. Although the kidneys are the first organs affected, and play a key role in morbidity and mortality, extrarenal multiorgan involvement can occur in patients with cystinosis, which is seen not only in adults but in early ages in untreated patients, patients with insufficient treatment, and in those that don't comply with treatment. The treatment of cystinosis consists of supportive treatment for Fanconi syndrome, and specific lifelong cystine-depleting therapy using oral cysteamine. There is strong evidence that as early as possible, initiation and ongoing appropriate therapy with cysteamine are essential for delaying the progression to kidney failure, end-organ damage, and extrarenal involvement. The present review aimed to evaluate the extra renal complications of cystinosis.

Morphological changes and their associations with clinical parameters in children with nephropathic cystinosis and chronic kidney disease prior to kidney replacement therapy over 25 years

BACKGROUND

Infantile nephropathic cystinosis (INC) is a rare lysosomal storage disorder, mostly and often firstly affecting the kidneys, together with impaired disharmonious growth and rickets, eventually resulting in progressive chronic kidney disease (CKD). With the introduction of cysteamine therapy, most pediatric patients reach adulthood with no need for kidney replacement therapy. Still, detailed changes in INC patients' clinical and morphological presentation over the past decades have not yet been thoroughly investigated.

METHODS

Two groups with a respective total of 64 children with INC and 302 children with CKD, both treated conservatively and aged 2 to 18 years, were prospectively observed in the time span from 1998 to 2022 with 1186 combined annual clinical and morphological examinations clustered into two measurement periods (1998 to 2015 and ≥ 2016).

RESULTS

In INC patients, thoracic proportion indices remained markedly increased, whereas body fat stores remained decreased over the past 25 years (+ 1 vs. below ± 0 z-score, respectively). Their CKD peers presented with overall improved growth, general harmonization of body proportions, and improved body fat stores, while INC patients only presented with an isolated significant increase in leg length over time (∆0.36 z-score). eGFR adjusted for age did not significantly change over the past 25 years in both groups. Alkaline phosphatase (ALP) showed a significant decrease in CKD patients over time, while remaining above normal levels in INC patients.

CONCLUSIONS

Disproportionate thoracic shape and impaired body fat stores remain the most characteristic morphological traits in INC patients over the past 25 years, while causal mechanisms remain unclear.

A New and Rapid LC-MS/MS Method for the Determination of Cysteamine Plasma Levels in Cystinosis Patients

Cystinosis is a rare lysosomal storage disorder caused by autosomal recessive mutations in the CTNS gene that encodes for the cystine transporter cystinosin, which is expressed on the lysosomal membrane mediating the efflux of cystine. Cysteamine bitartrate is a cystine-depleting aminothiol agent approved for the treatment of cystinosis in children and adults. In this study, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of cysteamine levels in plasma samples. This LC-MS/MS method was validated according to the European Medicines Agency (EMA)'s guidelines for bioanalytical method validation. An ultra-performance liquid chromatograph (UPLC) coupled with a 6470 mass spectrometry system was used for cysteamine determination. Our validated method was applied to plasma samples from n = 8 cystinosis patients (median, interquartile range (IQR) = 20.5, 8.5-26.0 years). The samples were collected before cysteamine oral administration (pre-dose) and 1 h after (post-dose). Our bioanalytical method fulfilled the regulatory guidelines for method validation. The cysteamine plasma levels in pre-dose samples were 2.57 and 1.50-3.31 μM (median and IQR, respectively), whereas the post-dose samples reported a cysteamine median concentration of 28.00 μM (IQR: 17.60-36.61). Our method allows the rapid determination of cysteamine plasma levels. This method was successfully used in cystinosis patients and, therefore, could be a useful tool for the evaluation of therapy adherence and for future pharmacokinetic (PK) studies involving a higher number of subjects.

Switching from immediate- to extended-release cysteamine in patients with nephropathic cystinosis: from clinical trials to clinical practice

Background

The purpose of this study is to evaluate the effectiveness and safety of switching from immediate-release (IR) to extended-release (ER) cysteamine in patients with nephropathic cystinosis (NC) in Spain.

Methods

We conducted an observational, retrospective, multicentre study in NC patients who received IR cysteamine for at least 12 months, switched to ER cysteamine, and received it for at least 6 months before inclusion.

Results

Data were collected from nine patients (four children, five adults) 36 months before and after the switch. Despite the highly selected population, an improvement in growth, particularly in children and a significant reduction in hospitalization days was observed. A decrease in halitosis, body odour and gastrointestinal effects was reported in most of the patients who suffered before the switch, and the use of proton pump inhibitors (PPIs) decreased in some patients. The estimated glomerular filtration rate (eGFR) remained stable in patients with preserved kidney function. No significant changes in white blood cell (WBC) cystine levels were observed after the switch. There was no significant difference in the cysteamine dose received. However, some patients were receiving <50% of the recommended dose of cysteamine before and after the switch and showed elevated levels of WBC cystine.

Conclusions

Switching from IR to ER cysteamine in clinical practice reduces hospital stays, improves nutritional status and growth in paediatric patients and could help to enhance treatment tolerability by reducing side effects. Furthermore, the dosing of ER cysteamine could promote therapeutic compliance and positively affect the quality of life of the NC population.

Gastrointestinal challenges in nephropathic cystinosis: clinical perspectives

Gastrointestinal (GI) sequelae, such as vomiting, hyperacidity, dysphagia, dysmotility, and diarrhea, are nearly universal among patients with nephropathic cystinosis. These complications result from disease processes (e.g., kidney disease, cystine crystal accumulation in the GI tract) and side effects of treatments (e.g., cysteamine, immunosuppressive therapy). GI involvement can negatively impact patient well-being and jeopardize disease outcomes by compromising drug absorption and patient adherence to the strict treatment regimen required to manage cystinosis. Given improved life expectancy due to advances in kidney transplantation and the transformative impact of cystine-depleting therapy, nephrologists are increasingly focused on addressing extra-renal complications and quality of life in patients with cystinosis. However, there is a lack of clinical data and guidance to inform GI-related monitoring, interventions, and referrals by nephrologists. Various publications have examined the prevalence and pathophysiology of selected GI complications in cystinosis, but none have summarized the full picture or provided guidance based on the literature and expert experience. We aim to comprehensively review GI sequelae associated with cystinosis and its treatments and to discuss approaches for monitoring and managing these complications, including the involvement of gastroenterology and other disciplines.

Impact of compliance to oral cysteamine treatment on the costs of Kidney failure in patients with nephropathic cystinosis in the United Kingdom

BACKGROUND

Nephropathic Cystinosis (NC), a rare disease characterised by intra-lysosomal accumulation of cystine, results in progressive kidney failure (KF). Compliance to lifelong oral cysteamine, the only therapy, is often compromised. The relationship between compliance and costs of NC has not been previously formally assessed. The present study evaluates the impact of compliance on lifetime (direct) costs of treating KF in NC patients in the United Kingdom.

METHODS

A three-state (KF-free, post-KF, death) partitioned survival model was developed for hypothetical 'Good Compliance' (GC) and 'Poor Compliance' (PC) cohorts. Survival in the KF-free state was determined by a published regression function of composite compliance score (CCS). The CCS is a summation of annual compliance scores (ACS) over treatment duration prior to KF. ACSs are indexed on annual (average) leukocyte cystine levels (LCL). The Poor Compliance cohort was defined to reflect NC patients in a previous study with a mean LCL of 2.35 nmols nmol half-cystine/mg protein over the study period - and an estimated mean ACS of 1.64 over a 13.4 year treatment duration. The Good Compliance cohort was assumed to have an ACS of 2.25 for 21 years. Major KF costs were evaluated - i.e., dialysis, kidney transplants, and subsequent monitoring.

RESULTS

The mean CCS was 47 for the GC and 22 for the PC cohort respectively, corresponding to estimated lifetime KF costs of £92,370 and £117,830 respectively - i.e., a cost saving of £25,460/patient, or £1,005/patient for every 1-unit improvement in CCS.

CONCLUSION

This analysis indicates that lifetime costs of KF in NC can be reduced through improved treatment compliance with oral cysteamine.

Cystinosis

Cystinosis is a very rare autosomal recessive lysosomal storage disorder with an incidence of 1 : 150,000 - 1 : 200,000, and is caused by mutations in the CTNS gene encoding the lysosomal membrane protein cystinosin, which transports cystine out of the lysosome into the cytoplasm. As a result, accumulation of cystine occurs in almost all cells and tissues, especially in the kidneys, leading to multiple organ involvement. Introduction of drug therapy with cysteamine in the mid 1980s, along with the availability of renal replacement therapy in childhood, have dramatically improved patient outcome. Whereas patients used to die without therapy with end-stage renal failure during the first decade of life, nowadays most patients live well into adulthood without renal replacement therapy, and several reach 40 years. There is robust evidence that early initiation and sustained lifelong therapy with cysteamine are both essential for morbidity and mortality. The rarity of the disease and the multi-organ involvement present an enormous challenge for those affected and the providers of care for this patient group.

A novel sustained-release cysteamine bitartrate formulation for the treatment of cystinosis: Pharmacokinetics and safety in healthy male volunteers

The strict intake regimen of cysteamine bitartrate formulations, associated with side effects, is a concern for the treatment compliance in cystinosis therapy. Therefore, there is a need for a cysteamine formulation with an improved pharmacokinetic profile. This study investigated the pharmacokinetics, safety and tolerability of a new sustained‐release cysteamine dosage form, PO‐001, in healthy volunteers. This was a randomized, investigator‐blinded, three‐way cross‐over study to compare single doses (600 mg) of PO‐001 with Cystagon^® (immediate‐release) and Procysbi^® (delayed‐release). Collected blood samples were analyzed for plasma cysteamine concentrations and pharmacokinetic parameters were estimated by noncompartmental analysis. In addition, plasma cysteamine concentrations were analyzed using a population pharmacokinetic approach using NONMEM^®. Pharmacokinetics showed clear sustained‐release characteristics of PO‐001 over time with a lower C_max and longer T_max compared to Cystagon^® and Procysbi^®. All treatment‐emergent adverse events were of mild severity, with the exception of two subjects who reported moderate severity gastrointestinal problems including vomiting and diarrhea, which were related to Cystagon^® intake. Population PK simulations showed a favourable PK profile based on C_max and C_trough concentrations at steady state. In conclusion, a single dose of 600 mg PO‐001 was well tolerated with no findings of clinical concern. This new cysteamine bitartrate formulation showed pharmacokinetics of a sustained‐release formulation, which may be beneficial for the treatment of cystinosis patients. This study supports advancing this type of sustained‐release formulation into a subsequent study to confirm reduced dosing frequency with efficient control of white blood cells (WBCs) cystine levels. Netherlands Trial Registry (NTR) (NL67638.056.18).

Discrimination of cysteamine from mercapto amino acids through isoelectric point-mediated surface ligand exchange of β-cyclodextrin-modified gold nanoparticles

A pI-mediated R6G-β-CD@AuNPs system was designed for the first time for the discrimination of CA from GSH/Cys/Hcy in human serum samples.

Influence of supplemented coated-cysteamine on morphology, apoptosis and oxidative stress status of gastrointestinal tract

BACKGROUND

Cysteamine was coated to cover its odor and maintain the stability. However, coated cysteamine (CC) has not been clearly evaluated for its effects on the gastrointestinal mucosa status. We hypothesize that the appropriate CC supplementation in diet impacts the stomach and intestinal mucosa variously through regulating the morphology, apoptosis, and oxidative stress status in model of pigs.

RESULTS

The results showed that villus height increased (P < 0.05), and crypt depth decreased (P < 0.05) in the ileum when pigs were fed the diet with low cysteamine (LCS) compared with the control diet. The ileal lesion score in the LCS group was significantly (P < 0.01) lower than that in the control group, while the gastric lesion score in the CC group was significantly (P < 0.01) higher compared with that of the control group. It also showed that the activities of total superoxide dismutase (T-SOD) and diamine oxidase (DAO) were upregulated (P < 0.05) in the LCS group. In addition, Bax and caspase 3 immunore-activity increased (P < 0.01), and Bcl-2 immunoreactivity decreased (P < 0.01) in the gastric mucosa of pigs fed the diet with high cysteamine (HCS). The Bax and caspase 3 immunoreactivity decreased (P < 0.01), and Bcl-2 immunoreactivity increased (P < 0.01) in ileum mucosa of pigs fed the HCS diet.

CONCLUSIONS

Although moderate dietary coated cysteamine showed positive effects on GI mucosal morphology, apoptosis, and oxidative stress status, the excess coated cysteamine may cause apoptosis leading to GI damage in pigs.

A systematic literature review of cysteamine bitartrate in the treatment of nephropathic cystinosis

OBJECTIVES

To summarize available clinical evidence for cysteamine bitartrate preparations in the treatment of nephropathic cystinosis as identified through a systematic literature review (SLR).

METHODS

We searched MEDLINE, MEDLINE In-Process and Embase using Ovid with a predefined search strategy through 19 January 2016. All publicly available clinical reports on the use of delayed-release (DR) cysteamine bitartrate (Procysbi ¹ ) or immediate-release (IR) cysteamine bitartrate (Cystagon ² ) in patients with cystinosis were included.

RESULTS

We identified a total of 103 publications and 10 trial records. Of these, 9 studies describe DR cysteamine bitartrate (n = 267 patients), 42 describe IR cysteamine bitartrate (n = 1,427 patients) and in 53 studies the exact preparation was not specified (n = 906 patients). The vast majority of the studies used a non-randomized study design, with randomized clinical trials (RCTs) being scarce (1 study comparing DR and IR formulation) and case reports (n = 49) being the most common study design representing 47% of the total.

CONCLUSION

A substantial evidence base for cysteamine bitartrate in the treatment of nephropathic cystinosis was identified. However, the majority of the evidence was of relatively low quality, with evidence levels of 3 or 4.

Systematic review of outcome measures in pediatric eosinophilic esophagitis treatment trials

Background

Heterogeneity has been noted in the selection and reporting of disease-specific, pediatric outcomes in randomized controlled trials (RCTs). The consequence is invalid results or difficulty comparing results across trials. The primary objective of this systematic review was to assess primary outcome and outcome measure selection and reporting, in pediatric eosinophilic esophagitis (EoE) treatment trials. As secondary objectives, we compared trial disease definition to established concensus guidelines, and the efficacy of current EoE treatments.

Methods

We searched MEDLINE, EMBASE, The Cochrane Library, Cochrane Central Register of Controlled Trials (CENTRAL), and CINAHL since 2001. We also searched clinical trial registries (portal.nihr.ac.uk; clinicaltrials.gov; isrctn.com; and anzctr.org.au) and references of included studies. We included RCTs of EoE treatment in patients 0–18 years. Two authors independently assessed articles.

Results

Eleven studies met inclusion criteria. All identified primary outcomes, however, of 9 unique primary outcomes, only 2 were used in more than one study. In total, 25 unique primary and secondary outcome measures were employed for pediatric EoE treatment trials. Measurement properties and rationale for their selection was rarely provided. Uptake of consensus-based diagnostic criteria was 25 % in trials initiated after 2011. Due to the small number and heterogeneity of studies obtained, no meta-analysis of treatment efficacy could be undertaken. This SR was limited to exclusively pediatric RCTs.

Conclusions

The results of this study confirm the need for a standardized set of core outcomes that are universally reported in pediatric EoE trials. Consistent disease definition and standardized outcome reporting will facilitate meta-analyses across similar trials and inform future clinical decision-making.

Systematic review registration number CRD42013003798

Cystinosis: a review

Cystinosis is the most common hereditary cause of renal Fanconi syndrome in children. It is an autosomal recessive lysosomal storage disorder caused by mutations in the CTNS gene encoding for the carrier protein cystinosin, transporting cystine out of the lysosomal compartment. Defective cystinosin function leads to intra-lysosomal cystine accumulation in all body cells and organs. The kidneys are initially affected during the first year of life through proximal tubular damage followed by progressive glomerular damage and end stage renal failure during mid-childhood if not treated. Other affected organs include eyes, thyroid, pancreas, gonads, muscles and CNS. Leucocyte cystine assay is the cornerstone for both diagnosis and therapeutic monitoring of the disease. Several lines of treatment are available for cystinosis including the cystine depleting agent cysteamine, renal replacement therapy, hormonal therapy and others; however, no curative treatment is yet available. In the current review we will discuss the most important clinical features of the disease, advantages and disadvantages of the current diagnostic and therapeutic options and the main topics of future research in cystinosis.

Cysteamine in renal transplantation: A report of two patients with nephropathic cystinosis and the successful re-initiation of cysteamine therapy during the immediate post-transplant period

Nephropathic cystinosis is a rare disorder causing the accumulation of intracellular cystine crystals in tissues. The damage to the proximal tubules of the kidneys results in Fanconi syndrome, and patients with cystinosis experience the progression of chronic kidney disease, resulting in the need for kidney transplantation. Treatment of cystinosis with cysteamine has proven to be effective; however, it has many gastrointestinal side effects that are concerning for transplant specialists during the immediate post-transplant period. Transplant specialists routinely discontinue cysteamine therapy for up to six weeks to ensure proper immunosuppressant absorption. This practice is worrisome because it communicates the acceptability of lapses of cysteamine treatment to patients. It may be better to re-initiate cysteamine therapy shortly after transplantation while the patient is followed more closely by the transplant team. This report presents two pediatric patients with nephropathic cystinosis who successfully restarted cysteamine therapy in the immediate post-transplant period without issue in regard to immunosuppression absorption or gastrointestinal side effects. These cases challenge current practice of discontinuing cysteamine therapy during kidney transplantation, and immediate re-initiation of cysteamine therapy in cystinosis patients post-transplant should be considered.

Cystinosis in adult and adolescent patients: Recommendations for the comprehensive care of cystinosis

INTRODUCTION

Cystinosis is a rare lysosomal systemic disease that mainly affects the kidney and the eye. Patients with cystinosis begin renal replacement therapy during the first decade of life in absence of treatment. Prognosis of cystinosis depends on early diagnosis, and prompt starting and good compliance with cysteamine treatment. Kidney disease progression, extra-renal complications and shorter life expectancy are more pronounced in those patients that do not follow treatment. The objective of this work was to elaborate recommendations for the comprehensive care of cystinosis and the facilitation of patient transition from paediatric to adult treatment, based on clinical experience. The goal is to reduce the impact of the disease, and to improve patient quality of life and prognosis.

METHODS

Bibliographic research and consensus meetings among a multidisciplinary professional team of experts in the clinical practice, with cystinotic patients (T-CiS.bcn group) from 5 hospitals located in Barcelona.

RESULTS

This document gathers specific recommendations for diagnosis, treatment and multidisciplinary follow-up of cystinotic patients in the following areas: nephrology, dialysis,renal transplant, ophthalmology, endocrinology, neurology, laboratory, genetic counselling,nursing and pharmacy.

CONCLUSIONS

A reference document for the comprehensive care of cystinosis represents a support tool for health professionals who take care of these patients. It is based on the following main pillars: (a) a multi-disciplinary approach, (b) appropriate disease monitoring and control of intracellular cystine levels in leukocytes, (c) the importance of adherence to treatment with cysteamine, and (d) the promotion of patient self-care by means of disease education programmes. All these recommendations will lead us, in a second phase, to create a coordinated transition model between paediatric and adult care services which will contemplate the specific needs of cystinosis.

Cysteamine (Cystagon®) adherence in patients with cystinosis in Spain: successful in children and a challenge in adolescents and adults

Background

Cysteamine has improved survival and prognosis in cystinosis. Increasing numbers of patients reach adulthood and face new challenges such as compliance that wanes over time. The aim of this study was to evaluate adherence to cysteamine treatment in a group of cystinotic patients in Spain in an attempt to identify potential therapy pitfalls and improve the overall care of affected individuals. Despite the impact of cysteamine on prognosis, there is a paucity of data regarding adherence.

Method

Thirty-four cystinotic patients (21 male) 38% ≥18 years were enrolled in a voluntary, anonymous survey. Replies were obtained from patients (15/34), mothers (11/34), fathers (4/34) and both parents (4/34).

Results

Patient age (median and interquartile range) at diagnosis was 1 year (0.57–1), and patient age at Cystagon® initiation was also 1 year (0.8–1.8). Sixteen (47%) were kidney transplant (KTx) recipients; six were retransplanted. Age at first KTx 10 years (8.7–13.7). Patient understanding of multiorgan involvement in cystinosis: 4.1 organs reported; eye 97% and kidney 91%. Cysteamine was given by mother (100%) and father (83%) in <11 year olds, or self-administered (94%) in ≥11 year olds. Four daily doses in 89% versus 56% in <11 year olds or ≥11 year olds, with fixed schedule in 94% versus 50% in <11 or ≥11 year olds and progressive loss of reminders over time. Furthermore, 44% complained of unpleasant smell. Motivation for treatment compliance was 100% versus 40% in <11 versus ≥11 year olds, respectively. Disease impact in patients <18 years is as follows: school (29%), social (14%), ‘feeling different’ (10%); in patients ≥18 years: ‘feeling different’ (62%), professional (39%) and job absenteeism (31%). Referring physician: paediatric nephrologist (94%) and nephrologist (63%) in <11 versus ≥11 year olds. Ophthalmological follow-up: 83% versus 38% in <11 versus ≥11 year olds. Patient opinion of physician expertise: paediatric nephrologist (94%) and nephrologist (44%). New treatment options (65%) and better information (42%) were demanded to improve adherence.

Conclusion

Treatment with Cystagon is effective in young patients. However, adherence diminishes over time in adolescents and adults despite disease impact. Strategies such as better information on the disease, patient self-care promotion and facilitated transition to adult healthcare services are required to improve compliance and the clinical management of cystinosis.

Improving the prognosis of nephropathic cystinosis

Cystinosis is an autosomal recessive inherited lysosomal storage disease. It is characterized by generalized proximal tubular dysfunction known as renal Fanconi syndrome and causes end-stage renal disease by the age of about 10 years if left untreated. Extrarenal organs are also affected, including the thyroid gland, gonads, pancreas, liver, muscle, and brain. Treatment consists of administration of cysteamine, resulting in depletion of cystine that is trapped inside the lysosomes. Since cysteamine has a short half-life, it should be administered every 6 hours. Recently, a new delayed-release formulation was marketed, that should be administered every 12 hours. The first studies comparing both cysteamine formulations show comparable results regarding white blood cell cystine depletion (which serves as a measure for cystine accumulation in the body), while a slightly lower daily dose of cysteamine can be used.

Increased human dermal microvascular endothelial cell survival induced by cysteamine

BACKGROUND

Cystinosis is an autosomal recessive disease caused by intralysosomal cystine accumulation, treated with cysteamine. Recently, new adverse effects of cysteamine were reported. Skin biopsies showed microvascular proliferation (angioendotheliomatosis). To examine the mechanism of angioendotheliomatosis associated with cysteamine toxicity, we examined the effect of cysteamine on human dermal microvascular endothelial cells (HDMVEC).

METHODS

After cysteamine exposure (range 0-3.0 mM) during 24 h, cell viability was measured using water soluble tetrazolium salt-1 (WST-1) in both control HDMVEC and fibroblasts. Cell proliferation and apoptosis rate were measured in HDMVEC by bromodeoxyuridine (BrdU) incorporation and caspase 3 and caspase 7 activity, respectively. Intracellular glutathione (GSH) was measured in HDMVEC after cysteamine exposure of 0, 0.1 or 1.0 mM. Medium and cysteamine were refreshed every 6 h to mimic the in vivo situation. Next, cell viability in HDMVEC was measured after 24 h of GSH exposure (range 0-10.0 mM).

RESULTS

HDMVEC viability and proliferation increased after cysteamine exposure 0.03-3.0 mM (p < 0.01) and 0.03-1.0 mM (p = 0.01) respectively; cell viability in fibroblasts was not affected by incubation with cysteamine. Apoptosis remained unaffected by incubation with 0-1.0 mM cysteamine, 3.0 mM caused increased apoptosis. Intracellular GSH was significantly increased after incubation with cysteamine 0.1 mM (p = 0.02) and 1.0 mM (p < 0.01). HDMVEC viability increased after exposure to GSH 1.0-5.0 mM (p < 0.01).

CONCLUSION

Cysteamine concentrations, similar to those described in plasma of cystinosis patients, stimulate HDMVEC viability and proliferation and increase intracellular GSH content. We postulate that this mechanism might underlie angioendotheliomatosis induced by cysteamine.

Pharmacokinetic Studies of Cysteamine Bitartrate Delayed-Release

A twice-daily microsphere formulation of cysteamine bitartrate has been developed for cystinosis and other potential applications. To date, there are no published pharmacokinetic data for cysteamine bitartrate delayed-release in healthy adults. Three randomized open-label, crossover studies to determine the effects of fasting, high fat, and carbohydrate meals on the bioavailability of cysteamine bitartrate delayed-release (600 mg) administered in capsule or sprinkle form to healthy adults. Adverse events were monitored. Fifty-eight adults were studied. Cysteamine absorption (AUC0-24 hours ) was the same for capsule and sprinkle forms during all meal/fasting states. The AUC0-24 hours for capsules while fasted, 30 and 120 minutes before a carbohydrate meal and during a high fat meal were 6,313 ± 329, 4,616 ± 878, 6,691 ± 669, 2,572 ± 295 minutes × µM, respectively, and the mean Cmax values were 29.4 ± 1.7, 20.7 ± 4.9, 31.6 ± 3.0, and 10.9 ± 1.7 µM, respectively. The mean Tmax following fasting and high fat meal were about 3 and 6 hours, respectively. Minor transient GI adverse events occurred. Cysteamine bitartrate delayed-release capsule and sprinkle forms are bioequivalent and optimal absorption occurs during fasting state. High fat diet reduces drug absorption, increases the Tmax and should be avoided at the time of drug ingestion. Cysteamine bitartrate delayed-release (RP103) is best ingested >30 minutes before a carbohydrate-rich meal.

Treatment of cystinosis with delayed-release cysteamine: 6-year follow-up

BACKGROUND

Patients with nephropathic cystinosis are required to take 6-hourly immediate-release cysteamine (Cystagon®) to reduce disease progression. This arduous regimen affects quality of life, disrupts sleep, and may result in non-compliance with therapy. Enteric-coated cysteamine bitartrate (EC-cysteamine) was developed as a "proof-of-concept" formulation for twice-daily ingestion. Previous reports have shown this therapy to be effective up to a mean of 14 months.

CASE-DIAGNOSIS/TREATMENT

Two subjects (aged 13 and 15 years) received EC-cysteamine for 5-6 years at 60-65 % of their previous total daily dose of immediate-release cysteamine given at 6-h intervals. White blood cell (WBC) cystine levels were monitored every 1-3 months.

CONCLUSION

The administration of EC-cysteamine did not result in any change in mean trough WBC cystine levels or any deterioration in the estimated glomerular filtration rate, thyroid, or liver function, suggesting that delayed-release, twice-daily EC-cysteamine is an effective long-term treatment alternative to immediate-release cysteamine given at 6-h intervals.

Clinical features distinguish eosinophilic and reflux-induced esophagitis

BACKGROUND AND OBJECTIVES

Diagnosing eosinophilic esophagitis (EoE) depends on intraepithelial eosinophil count of ≥15 eosinophils per high-power field (HPF); however, differentiating EoE from gastroesophageal reflux disease (GERD) continues to be a challenge because no true "criterion standard" criteria exist. Identifying clinical and endoscopic characteristics that distinguish EoE could provide a more comprehensive diagnostic strategy than the present criteria. The aim of the study was to determine symptoms and signs that can be used to distinguish EoE from reflux esophagitis.

METHODS

Adult and pediatric patients with EoE were identified by present diagnostic guidelines including an esophageal biopsy finding of ≥15 eosinophils/HPF. Patients with GERD were age-matched one to one with patients with EoE. Clinical, endoscopic, and histologic information at the time of diagnosis was obtained from the medical record and compared between pairs by McNemar test. A conditional logistic regression model was created using 6 distinguishing disease characteristics. This model was used to create a nomogram to differentiate EoE from reflux-induced esophagitis.

RESULTS

Patients with EoE were 75% men and 68% had a history of atopy. Many aspects of EoE were statistically distinct from GERD when controlling for age. Male sex, dysphagia, history of food impaction, absence of pain/heartburn, linear furrowing, and white papules were the distinguishing variables used to create the logistic regression model and scoring system based on odds ratios. The area under the curve of the receiver-operator characteristic curve for this model was 0.858.

CONCLUSIONS

EoE can be distinguished from GERD using a scoring system of clinical and endoscopic features. Prospective studies will be needed to validate this model.

Cysteamine: an old drug with new potential

Cysteamine is an amino thiol with the chemical formula HSCH2CH2NH2. Endogenously, cysteamine is derived from coenzyme A degradation, although its plasma concentrations are low. Most experience with cysteamine as a drug originates from the field of the orphan disease cystinosis, in which cysteamine is prescribed to decrease intralysosomal cystine accumulation. However, over the years, the drug has been used for several other applications both in vitro and in vivo. In this article, we review the different applications of cysteamine, ending with an overview of ongoing clinical trials for new indications, such as neurodegenerative disorders and nonalcoholic fatty liver disease (NAFLD). The recent development of an enteric-coated cysteamine formulation makes cysteamine more patient friendly and will extend its applicability for both old and new indications.

A potential new method to estimate tissue cystine content in nephropathic cystinosis

OBJECTIVES

To evaluate intestinal mucosal cystine crystal (CC) load as a way to estimate tissue cystine content in children with cystinosis.

STUDY DESIGN

Intestinal mucosal biopsies were obtained endoscopically from children (ages 2-18 years) with cystinosis. Using a special processing technique, CC within histiocytes were easily visible and enumerable in the mucosal tissue. Mean CC counts, calculated from stomach and duodenum combined (CC-GD), were correlated with duration of cysteamine treatment, estimated glomerular filtration rate (eGFR), and mean white blood cells (WBC) cystine levels.

RESULTS

Seventeen subjects (6 male) were enrolled in 2 studies from 2001 and 2003. The CC-GD count (mean 12.5 ± 1.41 crystals/histiocyte) was lower than the colonic crystal count (mean 23.6 ± 3.38, P = .0031). Nine of 17 subjects underwent repeated endoscopy 2 years later and the trend for CC-GD was to decrease over time (P = .065). Biopsies, however, were never completely depleted of CC. In subjects who were diagnosed before age 18 months, the percent change from baseline of both eGFR and CC-GD were inversely correlated (P = .026). Mean WBC cystine levels were positively correlated with CC-GD (P = .023).

CONCLUSIONS

CC are easily visible in the intestinal mucosa. CC-GD counts appear to correlate with eGFR and may help monitor response to treatment. Even when mean WBC cystine levels are low, the mucosal CC are not depleted suggesting that tissue cysteamine levels may not achieve therapeutic efficacy.

Macrophage-related diseases of the gut: a pathologist's perspective

The resident macrophages of the gastrointestinal tract represent the largest population of macrophages in the human body and are usually located in the subepithelial lamina propria. This strategic location guarantees a first-line defense to the huge numbers of potentially harmful bacteria and antigenic stimuli that are present in the intestinal lumen. In non-inflamed mucosa, macrophages phagocytose and kill microbes in the absence of an inflammatory response. However, in the event of an epithelial breach and/or microbial invasion, new circulating monocytes and lymphocytes will be recruited to the damaged area of the gut, which will result in the secretion of proinflammatory mediators and engage a protective inflammatory response. Although macrophages are usually not conspicuous in normal mucosal samples of the gut, they can easily be detected when they accumulate exogenous particulate material or endogenous substances or when they become very numerous. These events will mostly occur in pathologic conditions, and this review presents an overview of the diseases which are either mediated by or affecting the resident macrophages of the gut.

A randomized controlled crossover trial with delayed-release cysteamine bitartrate in nephropathic cystinosis: effectiveness on white blood cell cystine levels and comparison of safety

BACKGROUND AND OBJECTIVES

Immediate-release cysteamine bitartrate (Cystagon; Mylan Pharmaceuticals, Canonsburg, PA) may prevent or delay kidney transplantation and other serious outcomes in patients with cystinosis, but has never been subjected to a prospective clinical trial. Cystagon efficacy requires strict lifelong dosing every 6 hours. Such a dosing schedule and Cystagon-associated side effects are often cited by patients as reasons for nonadherence.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This open-label, randomized, controlled, crossover trial was powered to show that a new delayed-release formulation of cysteamine bitartrate, RP103, taken every 12 hours, was noninferior to Cystagon for maintenance of white blood cell (WBC) cystine at levels associated with optimal outcomes in the disease.

RESULTS

Forty-three patients were randomized. Using a mixed-effects statistical analysis model, the least-squares mean peak value of WBC cystine level was 0.62±0.05 nmol 1/2 cystine/mg protein after 12 hours under RP103 and 0.54±0.05 nmol 1/2 cystine/mg protein after 6 hours under Cystagon, a difference of 0.08±0.04 nmol 1/2 cystine/mg protein (95.8% confidence interval, 0-0.16). The average steady-state total daily dose of RP103 was 82% of the incoming steady-state total daily dose of Cystagon. There were three-fold more gastrointestinal side effects compared with using Cystagon.

CONCLUSIONS

A new delayed-release Q12H formulation of cysteamine bitartrate is not inferior to the Q6H formulation (Cystagon) in maintaining low WBC cystine levels in patients with cystinosis but at a lower total daily dose.

Cysteamine suppresses invasion, metastasis and prolongs survival by inhibiting matrix metalloproteinases in a mouse model of human pancreatic cancer

Background

Cysteamine, an anti-oxidant aminothiol, is the treatment of choice for nephropathic cystinosis, a rare lysosomal storage disease. Cysteamine is a chemo-sensitization and radioprotection agent and its antitumor effects have been investigated in various tumor cell lines and chemical induced carcinogenesis. Here, we investigated whether cysteamine has anti-tumor and anti-metastatic effects in transplantable human pancreatic cancer, an aggressive metastatic disease.

Methodology/Principal Findings

Cysteamine's anti-invasion effects were studied by matrigel invasion and cell migration assays in 10 pancreatic cancer cell lines. To study mechanism of action, we examined cell viability and matrix metalloproteinases (MMPs) activity in the cysteamine-treated cells. We also examined cysteamine's anti-metastasis effect in two orthotopic murine models of human pancreatic cancer by measuring peritoneal metastasis and survival of animals. Cysteamine inhibited both migration and invasion of all ten pancreatic cancer cell lines at concentrations (<25 mM) that caused no toxicity to cells. It significantly decreased MMPs activity (IC₅₀ 38–460 µM) and zymographic gelatinase activity in a dose dependent manner in vitro and in vivo; while mRNA and protein levels of MMP-9, MMP-12 and MMP-14 were slightly increased using the highest cysteamine concentration. In vivo, cysteamine significantly decreased metastasis in two established pancreatic tumor models, although it did not affect the size of primary tumors. Additionally, cysteamine prolonged survival of mice in a dose-dependent manner without causing any toxicity. Similar to the in vitro results, MMP activity was significantly decreased in animal tumors treated with cysteamine. Cysteamine had no clinical or preclinical adverse effects in the host even at the highest dose.

Conclusions/Significance

Our results suggest that cysteamine, an agent with a proven safety profile, may be useful for inhibition of metastasis and prolonging the survival of a host with pancreatic cancer.

Cysteamine toxicity in patients with cystinosis

OBJECTIVE

To report new adverse effects of cysteamine.

STUDY DESIGN

Detailed clinical information was obtained from the patients' physicians.

RESULTS

New adverse events were reported in 8 of 550 patients with cystinosis treated with cysteamine in Europe during the last 5 years. Detailed clinical information was not available for 2 of these patients, 1 of whom died from cerebral ischemia. The 6 evaluable patients developed vascular elbow lesions (6/6), neurologic symptoms (1/6), bone and muscle pain (2/6), and/or skin striae (2/6). Analysis of biopsy specimens from the elbow lesions demonstrated angioendotheliomatosis with irregular collagen fibers. In 3 of the 6 patients, the daily cysteamine dose exceeded the recommended maximum of 1.95 g/m(2)/day. Dose reduction led to improvement of signs and symptoms in all 6 patients, suggesting a causal relationship with cysteamine administration.

CONCLUSION

Cysteamine administration can be complicated by the development of skin, vascular, neurologic, muscular, and bone lesions. These lesions improve after cysteamine dose reduction. Doses >1.95 g/m(2)/day should be prescribed with great caution, but underdosing is not advocated.

Duodenal ulceration in a patient with celiac disease and plasminogen I deficiency: coincidence or cofactors?

Celiac disease (CD) is a gluten-dependent inflammatory disease of the small bowel that affects up to 1% of the worldwide population. Despite severe mucosal abnormalities including total villous atrophy and autoantibody deposition, duodenal ulcer is not a feature of CD. However, a recent study found an elevated rate of peptic ulcer disease in patients with CD. Plasminogen deficiency (PLD) is an autosomal recessive disease that causes pseudomembranous lesions in different organs, but gastrointestinal involvement is rare. Here we report the case of a 6-year-old girl who had a sudden onset of hematemesis caused by duodenal ulcer. On the basis of mucosal atrophy, elevated celiac antibody levels, decreased plasminogen serum activity, and homozygous missense mutation R216H in the plasminogen gene, CD and PLD were diagnosed. This report is, to our knowledge, the first description of the 2 entities, and results of our double-immunofluorescent studies also suggest that both diseases may have a role in the ulceration process. Excessive amounts of fibrin deposition due to PLD caused the distortion of the vessels and was responsible for the unusual celiac immunoglobulin A and tissue transglutaminase 2 in vivo binding pattern. On the basis of this result, patients with CD and unknown cause of gastrointestinal ulcer may require investigation for PLD.

Improvement in the renal prognosis in nephropathic cystinosis

BACKGROUND AND OBJECTIVES

Nephropathic cystinosis (NC) is an autosomal recessive disorder occurring in one to two per 100,000 newborns. Because of the rarity of NC, long-term outcome data are scarce.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

245 NC patients from 18 countries provided data to the ESPN/ERA-EDTA registry. We matched NC patients on renal replacement therapy (RRT) to non-NC children on RRT.

RESULTS

Between 1979 and 2008, mean age at the start of RRT among NC children increased by 0.15 year per calendar year (95% confidence interval, 0.10 to 0.21) from 8.8 to 12.7 years, whereas we did not observe this in non-NC children. Five-year survival after the start of RRT improved in NC patients from 86.1% (before 1990) to 100% (since 2000) as compared with the control population (89.6% and 94.0%). NC patients received a renal allograft more often (relative risk, 1.09; 95% confidence interval, 1.00 to 1.17) as compared with matched RRT children, and 5-year graft survival was better (94.0% versus 84.0%). NC dialysis patients were less often hypertensive than non-NC children matched for age, country, and dialysis modality (42.7% versus 51.7%) and had lower parathyroid hormone levels (median, 56 versus 140 pg/ml). Although height at start of RRT slightly improved during the past decade, children with NC remained significantly shorter than non-NC children at the start of RRT.

CONCLUSIONS

We demonstrated improved survival of the renal function as well as better patient and graft survival after the start of RRT in a large European cohort of NC patients over the last two decades.

Enteric-coated cysteamine for the treatment of paediatric non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a common cause of liver disease in children. Hepatic fat accumulation and oxidative stress contribute to its pathogenesis. Cysteamine bitartrate readily traverses cellular membranes and is a potent antioxidant.

AIM

To evaluate the safety and efficacy of enteric-coated (EC) cysteamine in children with NAFLD.

METHOD

Children, aged ≥10 y, meeting screening criteria with biopsy-proven NAFLD and serum ALT ≥60 IU/L, received twice-daily EC-cysteamine for 24 weeks. Monthly ALT, AST, body mass index (BMI) and gastrointestinal symptom scores were measured. Subjects with >50% reduction or normalisation of ALT achieved the primary endpoint.

RESULTS

Of the 13 children enrolled (mean age 14.0 years), 11 completed EC-cysteamine therapy (mean dose 15.2 mg/kg/day) and were included in the final analysis. For these 11 subjects, the mean ALT levels at baseline and 24 weeks were 120.2 and 55 IU/L respectively (P = 0.002), and the AST levels were 60 and 36 IU/L respectively (P = 0.007). The primary endpoint was reached in 7 and normalisation (≤40 IU/L) of ALT in 5. After 24 week therapy, mean adiponectin levels increased (P = 0.009) and CK-18 fragment levels decreased (P = 0.013), insulin levels remained unchanged (P = 0.99). Mean leptin levels were decreased in responders (P = 0.044). Mean BMI was 34.5 at baseline and 34.2 kg/m(2) after treatment (P = 0.35). Mean symptom scores at baseline (1.1) and at 24 weeks (0.7) were similar. No major adverse events were reported.

CONCLUSIONS

Enteric-coated cysteamine reduces ALT and AST levels in children with NAFLD without reduction in body mass index. Further studies will evaluate optimal cysteamine therapeutic dose and effect on liver histology in NAFLD (Clinicaltrials.gov protocol ID: 07-1699).

Pharmacokinetics of enteric-coated cysteamine bitartrate in healthy adults: a pilot study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Cysteamine bitartrate is taken lifelong, every 6 h and for the treatment of cystinosis. Recent studies using cysteamine for for other diseases such as neurodegenerative disorders adopt the same dosing regimen for cysteamine. Regular cysteamine bitartrate (Cystagon) may cause upper gastrointestinal symptoms in some patients.

WHAT THIS STUDY ADDS

This is the only study that provides pharmacokinetic data for cysteamine delivered in an enteric-release preparation in normal subjects. EC-cysteamine is very well tolerated and does not cause increased gastrin concentrations, even at relatively high doses. EC-cysteamine at the higher dose results in better drug uptake as measured by Cmax and AUC and is more likely to be effective.

AIMS

Cysteamine bitartrate (Cystagon) is the approved treatment for cystinosis. Poor compliance and patient outcome may occur because the drug needs to be taken every 6 h and in some patients causes gastrointestinal symptoms due to hypergastrinaemia. A formulation of cysteamine requiring twice daily ingestion would improve the quality of life for these patients. This study compares the pharmacokinetics and gastrin production following cysteamine bitartrate non-enteric-coated and cysteamine bitartrate enteric-coated in normal healthy subjects.

METHODS

Enteric-coated cysteamine was prepared. Following single doses of cysteamine bitartrate non-enteric-coated 450 mg and cysteamine bitartrate enteric-coated 450 mg and 900 mg, serial plasma cysteamine and gastrin concentrations were measured. Two subjects also received cysteamine bitartrate non-enteric-coated 900 mg. Gastrointestinal (GI) symptoms were recorded.

RESULTS

Six healthy adults (mean age 20.7 years, range 18-24 years; mean weight 59.3 kg) received drug. All post-dose gastrin concentrations were within the normal range (<100 pg ml(-1)). The tmax following cysteamine bitartrate non-enteric-coated (mean and SD is 75+/-19 min) was shorter than cysteamine bitartrate enteric-coated (220+/-74 min) (P=0.001), but only the Cmax and AUC estimates following 900 mg cysteamine bitartrate enteric-coated were significantly greater than any of the other preparations or doses (P<0.05). One patient had GI symptoms following both 900 mg cysteamine bitartrate non-enteric-coated and cysteamine bitartrate enteric-coated.

CONCLUSION

Although patient numbers were low, single high doses of cysteamine bitartrate enteric-coated were better tolerated than similar doses of cysteamine bitartrate non-enteric-coated in the healthy subjects and all had normal gastrin concentrations. The delayed tmax following cysteamine bitartrate enteric-coated suggested that the cysteamine was released enterically.

Oral viscous budesonide is effective in children with eosinophilic esophagitis in a randomized, placebo-controlled trial

BACKGROUND & AIMS

Eosinophilic esophagitis (EoE) is caused by immunologic reactions to ingested/inhaled allergens. The diagnosis is considered if >or=15 eosinophils per high-powered field (eos/hpf) are detected in mucosal biopsies. Placebo-controlled studies have not been conducted to evaluate the safety and efficacy of oral viscous budesonide (OVB).

METHODS

Children with EoE were randomly assigned to groups that were given OVB (n=15) or placebo (n=9). Patients<5 feet and >or=5 feet tall received 1 mg and 2 mg OVB daily, respectively. All patients received lansoprazole. Duration of treatment was 3 months, followed by repeat endoscopy and biopsies. Patients were classified as responders if their peak eosinophil counts were <or=6 eos/hpf, partial responders were 7-19 eos/hpf, and nonresponders were >or=20 eos/hpf. Baseline and post-treatment symptoms and endoscopic and histologic features were scored.

RESULTS

Thirteen (86.7%) children given OVB (P<.0001) and none who received placebo (P=.3) were classified as responders. Mean pre-/post-treatment peak eosinophil counts were 66.7 and 4.8 eos/hpf, respectively, in the group given OVB (P<.0001); they were 83.9 and 65.6 eos/hpf, respectively, in the group given placebo (P=.3). In the group given OVB, there were significant reductions from baseline values in proximal (P=.002), mid (P=.0003), and distal (P=.001) esophageal eosinophilia. After OVB therapy, compared with baseline, the mean symptom (P=.0007), endoscopy (P=.0005), and histology scores improved (P=.0035) significantly.

CONCLUSIONS

OVB is an effective treatment of pan-esophageal disease in children with EoE. OVB improves symptoms and endoscopic and histologic features. Proton pump inhibitor single therapy did not significantly improve esophageal eosinophilia or symptoms of EoE.

Long-term treatment of cystinosis in children with twice-daily cysteamine

OBJECTIVE

Cystinosis causes renal and other organ failure. Treatment with 6-hourly cysteamine bitartrate (Cystagon, Mylan, Morgantown, West Virginia) reduces intracellular cystine and the rate of organ deterioration. A recent study showed that an enteric-release cysteamine required less frequent daily dosing. This report describes the long-term use of enteric-coated (EC) cysteamine bitartrate (Cystagon) in children with cystinosis.

STUDY DESIGN

After a pharmacokinetic and pharmacodynamic study of EC-cysteamine in children with cystinosis, 5 patients remained on twice-daily treatment. White blood cell cystine levels were measured 12 hours after ingestion every 4 to 8 weeks. These levels were then compared with the patient's previous 6-h post-dose levels taken while on regular cysteamine bitartrate before entering the study. Blood chemistry was also measured.

RESULTS

Five children with cystinosis (mean age, 9 years; range, 8 to 17 years) who previously took cysteamine bitartrate (mean dose, 47 mg/kg body wt), received EC-cysteamine for 10 to 27 months (mean dose, 25 mg/kg body wt) and had mean white blood cell cystine levels of 0.77 and 0.71 nmol half-cystine/mg protein, respectively. During the study period, patients maintained adequate growth and there was no significant deterioration in renal or thyroid function. Two children were required to restart acid suppression after 6 months on EC-cysteamine therapy.

CONCLUSIONS

Long-term, twice-daily EC-cysteamine, given at approximately 60% of the previous daily dose of cysteamine bitartrate, was effective at maintaining white blood cell cystine levels within a satisfactory range. There was no significant deterioration in renal or thyroid function.

Twice-daily cysteamine bitartrate therapy for children with cystinosis

OBJECTIVE

Cystinosis causes renal and other organ failure. Regular 6-hourly cysteamine bitartrate (Cystagon; Mylan, Morgantown, West Virginia) reduces intracellular cystine and the rate of organ deterioration. A formulation of cysteamine requiring less frequent dosing may improve compliance and possibly patient outcome.

METHODS

Enteric-release cysteamine was prepared. For a period of 1 month, patients received their regular cysteamine dose every 6 hours (stage I). The patients then underwent pharmacokinetic and pharmacodynamic studies following washout periods using single-doses of cysteamine and enteric-release cysteamine (stage II). Finally, the patients commenced regular enteric-release cysteamine therapy (stage III). Weekly trough white blood cell (WBC) cystine levels were recorded.

RESULTS

Seven children with cystinosis (mean age, 11.8 years; range, 8-17 years) who received cysteamine and enteric-release cysteamine (mean dose, 45 and 28.8 mg/kg body weight/day, respectively) had mean WBC cystine levels of 0.7+/-0.3 and 0.41+/-0.22 nmol half-cystine/mg protein in study stages I and III, respectively. Study stage II showed that the mean time (T(max)) to reach the maximum plasma cysteamine level (C(max)) was longer for enteric-release cysteamine than for cysteamine (176 minutes vs 60 minutes; P=.001), but the mean C(max) at the same dose was similar. Mean serum gastrin levels were similar after ingestion of cysteamine and enteric-release cysteamine.

CONCLUSIONS

Twelve-hour enteric-release cysteamine, given at approximately 60% of the previous daily dose of cysteamine, was effective in maintaining trough WBC cystine levels within a satisfactory range.

A symptom scoring tool for identifying pediatric patients with eosinophilic esophagitis and correlating symptoms with inflammation

BACKGROUND

Eosinophilic esophagitis (EE) is an increasingly recognized allergic disease entity that is difficult to distinguish clinically from other causes of esophagitis, especially gastroesophageal reflux disease (GERD). To our knowledge, there are no prospectively analyzed or validated symptom scoring tools for pediatric patients with EE and no prospective evaluation correlating symptoms with tissue inflammation.

OBJECTIVES

To prospectively analyze a symptom scoring tool's ability to distinguish pediatric patients with EE from those with GERD and from control patients with and without allergies and to correlate symptoms with tissue inflammation.

METHODS

A prospective study of a symptom scoring tool given to patients with EE (n = 35 not receiving EE targeted therapy), patients with GERD (n = 27 not undergoing acid suppression), allergic control patients (n = 24), and nonallergic control patients (n = 14) at an academic pediatric hospital. Histology and endoscopy scores were correlated with symptom complaints.

RESULTS

The total symptom score was higher among patients with EE (mean, 6.51; 95% confidence interval [CI], 5.50-7.53) and GERD (mean, 5.44; 95% CI, 4.64-6.25) than in allergic (mean, 0.92; 95% CI, 0.28-1.55) and nonallergic (mean, 1.00; 95% CI, 0.40-1.60) patients (P < .001). Patients with EE and GERD complained of more nausea/vomiting, abdominal pain, heartburn/regurgitation, and nocturnal awakening than control groups (P < .001). Only dysphagia (mean, 0.9 [95% CI, 0.7-1.2] in EE patients vs 0.4 [95% CI, 0.2-0.7] in GERD patients) and anorexia/early satiety (mean, 1.4 [95% CI, 1.2-1.6] in EE patients vs 0.8 [95% CI, 0.5-1.1] in GERD patients) discriminate EE from GERD (P < .01). These symptoms also correlated with the severity of histologic and endoscopic findings (P < .05).

CONCLUSION

Dysphagia and anorexia/early satiety identify pediatric patients with EE and correlate symptoms with tissue inflammation.

Intravenous delivery of cysteamine for the treatment of cystinosis: association with hepatotoxicity

Nephropathic cystinosis is a lysosomal storage disorder, which, if untreated, results in renal failure by age 10 years. Oral cysteamine has been shown to preserve renal function in these patients. In this study, a 2-year-old girl with nephropathic cystinosis and severe gastrointestinal dysmotility was treated with intravenous (i.v.) administration of cysteamine hydrochloride (HCl). This is only the second report of long-term i.v. cysteamine therapy for nephropathic cystinosis. Unlike the treatment in the previous case, however, treatment in our patient was limited by liver toxicity.

Oral viscous budesonide: a potential new therapy for eosinophilic esophagitis in children

BACKGROUND

Eosinophilic esophagitis (EE) is a disorder characterized typically by pan-esophageal eosinophilia. We evaluate a palatable, long-acting topical corticosteroid preparation for the treatment of EE.

STUDY DESIGN

This is a retrospective analysis of symptoms, endoscopic and histologic findings, efficacy, and safety of treatment in children with EE receiving oral viscous budesonide. Response to therapy was determined histologically by the number of eos/hpf. Patients were classified by histology into responders (0-7 eos/hpf), partial responders (8-23 eos/hpf), and nonresponders (>/=24 eos/hpf). A symptom score (max. 14) and an EE endoscopy score (max. 8) were used to compare data.

RESULTS

In 20 children (mean age 5.5 yr, median age 4.1 yr) the mean highest eosinophil count was 87 eos/hpf (range 30-170) before and 7 eos/hpf (range 0-50, P < 0.0001) after therapy. There were 16 (80%) responders, 1 partial responder, and 3 nonresponders. Commonest pretreatment symptoms were nausea, vomiting, pain, and heartburn. The mean symptom score fell from 4.4 to 0.8 (P < 0.0001) and the mean endoscopy score from 3.6 to 0.8 (P < 0.0001). No significant adverse events were reported. Morning cortisol levels were within normal limits.

CONCLUSIONS

Topical viscous budesonide is a safe and effective therapy for EE in young children.

Pharmacokinetics of cysteamine bitartrate following gastrointestinal infusion

AIMS

Although cysteamine was first used in the treatment of cystinosis in 1976 and approved by the FDA as cysteamine bitartrate (Cystagon) in 1994, surprisingly little pharmacological data are available for this compound. Cysteamine and its related drugs are currently being evaluated for the treatment of Huntington's and Parkinson's disease. The aim of te study was to understand the pharmacokinetics of cysteamine bitartrate following gastrointestinal infusion.

METHOD

Cysteamine bitartrate was delivered through a naso-enteric catheter into the stomach (n = 8), small intestine (n = 8) and caecum (n = 4) of normal subjects. Plasma cysteamine concentrations were determined using LC-MS/MS.

RESULTS

The rate and extent of drug absorption were assessed by comparing AUC(0, infinity), C(max) and t(max), among the gastrointestinal infusion sites. Total cysteamine exposure, expressed as area under the curve (AUC(0, infinity)) was greatest when the drug was infused into the small intestine (4331.3 +/- 1907.6 min x microM) followed by stomach (3901.9 +/- 1591.9 min x microM) and caecum (3141.4 +/- 1627.6 min x microM). Cysteamine infusion into the small intestine resulted in the most rapid rise to maximal plasma concentrations (t(max) = 21 +/- 0.56 min); t(max) was delayed to 50 +/- 26 min and 64 +/- 26 min after gastric and caecal infusion, respectively. The maximum cysteamine plasma concentration (C(max)) was reached after infusion of the drug into the small intestine (51 +/- 21 microM), which was higher than plasma C(max) concentrations after gastric (39 +/- 16 microM) and caecal infusion (23 +/- 15 microM).

CONCLUSIONS

The pharmacokinetic data generated help extend our understanding of cysteamine.

Understanding intestinal cysteamine bitartrate absorption

OBJECTIVES

To test the hypothesis that a controlled-release preparation of cysteamine, with fewer daily administrations, would improve the quality of life for patients with cystinosis.

STUDY DESIGN

A specifically designed nasoenteric tube was used to administer cysteamine directly into the stomach, small intestine (SI) and colon and serial plasma cysteamine, serum gastrin and leukocyte cystine levels were measured.

RESULTS

Eight control subjects (mean age 23.2 years) and 6 subjects with cystinosis (mean age 15.2 years) were studied. Cysteamine absorption (maximum concentration and area under the curve of the concentration-time gradient) was greater from the SI than stomach or cecum (P < .01). Leukocyte cystine depletion was greater after delivery of cysteamine into the SI than stomach or cecum; this effect was associated with the plasma cysteamine maximum concentration and area under the curve (P < .001 and < .02, respectively). Gastrin levels were not affected by site of drug delivery and were elevated only in patients with cystinosis with gastrointestinal symptoms.

CONCLUSIONS

The absorption of cysteamine and the effect of this agent on leukocyte cystine depletion are more profound after SI administration. Enteric-coated cysteamine, targeted for SI release, may require fewer daily dosages. Not all patients with cystinosis require acid-suppression therapy.

Strict cysteamine dose regimen is required to prevent nocturnal cystine accumulation in cystinosis

Cystinosis is an autosomal recessive disorder, caused by mutations in the lysosomal cystine carrier cystinosin, encoded by the CTNS gene. The disease generally manifests with Fanconi syndrome during the first year of life and progresses towards end stage renal disease before the age of 10 years. Cysteamine depletes intralysosomal cystine content, postpones the deterioration of renal function and the occurrence of extra-renal organ damage. Based on the pharmacokinetic data, patients with cystinosis are advised to use cysteamine every 6 h. The aim of this study was (1) to evaluate the cysteamine dose regimen in Dutch patients with cystinosis and (2) to determine morning polymorphonuclear (PMN) leukocyte cystine content 6 h vs 9 h after the last evening cysteamine dose. Only 5/22 of Dutch cystinosis patients ingested cysteamine every 6 h. Morning (8 a.m.) PMN cystine content in 11 examined patients was elevated 9 h after 12.5-15 mg/kg evening cysteamine dose compared to the value 6 h after the ingestion of the same dose (0.73+/-0.81 nmol vs 0.44+/-0.52 nmol cystine/mg protein, p =0.02). In conclusion, only the minority of Dutch cystinosis patients follows the recommended strict cysteamine dose regimen. We provide evidence that cysteamine has to be administered every 6 h, including the night, as it has much better effect for maintaining low PMN cystine levels.

Esomeprazole therapy for gastric acid hypersecretion in children with cystinosis

Oral cysteamine therapy prevents natural disease progression in children with cystinosis, but it may cause severe gastrointestinal (GI) symptoms through gastric acid-hypersecretion. The purpose of this study was to assess the value of esomeprazole in controlling cysteamine-induced acid-hypersecretion and GI symptoms in children with cystinosis. Subjects underwent upper GI endoscopy and biopsy, serum gastrin and cysteamine measurements as well as acid secretion studies (basal, maximal and peak acid output, BAO, MAO, PAO) before and during esomeprazole therapy. A symptom score (maximum 14 points) was devised to monitor symptoms. Twelve children (mean age 5.8 years) were studied. Cysteamine ingestion resulted in mean MAO and PAO significantly higher than mean BAO, both before and during esomeprazole therapy. PAO was usually within 60 min of cysteamine ingestion. Esomeprazole therapy significantly reduced MAO (P<0.01) and PAO (P<0.01). The mean symptom score fell from 6.4 to 0.7 (P<0.0001) during esomeprazole therapy. The mean final dose of esomeprazole was 1.7 mg/kg per day (range 0.7 mg/kg per day to 2.75 mg/kg per day). Plasma cysteamine levels were not affected by acid-suppression therapy. One child had multi-nucleated parietal cells. Cysteamine-induced gastric acid-hypersecretion and GI symptoms are dramatically reduced with esomeprazole therapy. Esomeprazole does not alter cysteamine absorption and is very well tolerated in children.

Swallowing dysfunction in 101 patients with nephropathic cystinosis: benefit of long-term cysteamine therapy

Nephropathic cystinosis is a rare, autosomal recessive lysosomal storage disorder caused by mutations in the CTNS gene that codes for a cystine transporter in the lysosomal membrane. Affected patients store 50-100 times the normal amounts of cystine in their cells, and suffer renal tubular and glomerular disease, growth retardation, photophobia, and other systemic complications, including a myopathy and swallowing dysfunction. Using videofluoroscopy and ultrasound examinations, we assessed the swallowing function of 101 patients with nephropathic cystinosis on their most recent admission to the National Institutes of Health Clinical Center between 1987 and 2004. These patients ranged in age from 6 to 45 years; more than half had significant complaints of swallowing difficulty. On examination of barium swallow, the oral, pharyngeal, and esophageal phases of swallowing were abnormal in 24%, 51%, and 73% of patients, respectively. The frequency of dysfunction increased with age for each phase of swallowing. Both the Swallowing Severity Score (a measure of dysfunction on barium swallow) and the Oral Muscle Composite Score (a reflection of vocal strength, oral-facial movement, and tongue and lip function) increased (that is, worsened) with the number of years that a patient was not receiving treatment with cysteamine, the cystine-depleting agent of choice in cystinosis. The severity scores decreased with the number of years on cysteamine therapy. The Swallowing Severity Score varied directly with the severity of muscle disease, but was not correlated with the presence or absence of the 57-kb CTNS deletion that commonly occurs in nephropathic cystinosis patients. We conclude that swallowing dysfunction in cystinosis presents a risk of fatal aspiration, correlates with the presence of muscle atrophy, and, based on cross-sectional data, increases in frequency with age and number of years without cysteamine treatment. Cystine-depleting therapy with cysteamine should be considered the treatment of choice for both pre- and posttransplant cystinosis patients.

Inhibidores de la bomba de protones en pediatría

In last years the use in the pediatric area of proton pump inhibitors (omeprazole, lansoprazole, pantoprazole, rabeprazole and esomeprazole) is more often, nevertheless the clinical trials carried out are poor. The aim of this work is to analyse the bibliography published about this kind of drugs in children and to make a revision of its use in the last seven years. More studies with omeprazole and lansoprazole have been developed, to be exact omeprazole and lansoprazole is present in 122 bibliographic appointments and 34 for lansoprazole, which include studies that demonstrate a good tolerance and efficacy. The remaining proton pump inhibitors count with very few studies. The main therapeutic indications were the eradication of Helicobacter pylori, gastroesophageal reflux disease and esophagitis. The number of patients included in the reviewed studies is quite heterogeneous, from 8 to 122 and the age range between 8 days and 17 years. On the other hand, it could be highlighted the non-existence of formulations adapted to the pediatric population and the difficulty of administration specially in the youngest patients. As in many other drugs, it would be necessary to carry out clinical trials in order to determinate the pharmacologic parameters at difference ages, which will allow a safe and effective administration, and its authorization by all Health Authorities.

Pharmacological treatment of nephropathic cystinosis with cysteamine

Cystinosis, clinically recognised since 1903, is an autosomal recessive lysosomal storage disease caused by mutations in CTNS. This gene codes for a lysosomal cystine transporter, whose absence leads to intracellular cystine crystals, widespread cellular destruction, renal Fanconi syndrome in infancy, renal glomerular failure in later childhood and other systemic complications. Before the availability of kidney transplantation, patients affected with cystinosis uniformly died during childhood. After solid organ transplantations became successful in the 1960s, cystinosis patients survived, but eventually developed life-threatening consequences of the disease (e.g., swallowing disorders). Since the introduction of cysteamine into the pharmacological management of cystinosis, well-treated adolescent and young adult patients have experienced normal growth and maintenance of renal glomerular function. Oral cysteamine therapy is given at doses of 60 - 90 mg/kg/day q.i.d. every 6 h, and generally achieves approximately 90% depletion of cellular cystine, as measured in circulating leucocytes. Cysteamine (and kidney transplantation) have commuted the death sentence of cystinosis into a nearly normal life with a chronic disease. Because treatment with oral cysteamine can prevent, or significantly delay, the complications of cystinosis, early and accurate diagnosis, as well as proper treatment, is critical.