Treatment of Mitochondrial Neurogastrointestinal Encephalomyopathy with Dialysis

OBSERVATION Treatment of Mitochondrial Neurogastrointestinal Encephalomyopathy With Dialysis

Haluˆk Yavuz, MD; Ahmet O¨ zel, MD; Mette Christensen, MSc; Ernst Christensen, PhD; Marianne Schwartz, PhD; Mithat Elmaci, MD; John Vissing, MD, PhD

Objective: To study the effect of continuous ambula- Results: Dialysis stopped vomiting and reduced ab- tory peritoneal dialysis on nucleoside levels and clinical dominal pain, and the patient gained 5 kg in weight and course in a patient with mitochondrial neurogastroin- started to menstruate again. Symptoms returned if dialy- testinal encephalomyopathy (MNGIE). sis was paused. Dialysis did not affect plasma nucleoside levels. Patient: We studied a patient with genetically verified MNGIE, who prior to treatment had lost weight progres- Conclusions: This study shows an unambiguous clini- sively, developed amenorrhea, vomited multiple times cal benefit of peritoneal dialysis on gastrointestinal daily, and had abdominal pain. symptoms in MNGIE. Dialysis did not affect nucleoside levels, indicating elevated thymidine and deoxyuridine Intervention: The patient was treated with peritoneal levels are not solely responsible for the pathogenesis of dialysis for 3 years, and the effect on symptoms and MNGIE. plasma concentrations of thymidine and deoxyuridine were monitored. Arch Neurol. 2007;64:435-438

ITOCHONDRIAL NEURO- treatment for the condition is still lack- gastrointestinal en- ing. In this study, we report the use of con- cephalomyopathy tinuous ambulatory peritoneal dialysis (MNGIE) is a rare au- (CAPD) as a treatment for MNGIE. tosomal recessive mul- tisystem disorder characterized by exter- M REPORT OF A CASE nal ophthalmoplegia, gastrointestinal dysmotility and pain, cachexia, periph- eral neuropathy, and leukoencephalopa- A girl with consanguineous parents pre- thy. The disease is caused by mutations in sented with episodic vomiting and epigas- the gene encoding thymidine phosphory- tric pain at age 15 years. She was cachec- lase (ECGF1).1 Thymidine phosphory- tic (weight, 28 kg; height, 154 cm) and had lase is a cytosolic enzyme that regulates a low blood pressure (85/65 mm Hg). The pyrimidine nucleoside levels by phospho- patient had generalized muscle weakness rolytic catabolism of deoxyuridine and and atrophy, mild bilateral ophthalmople- Author Affiliations: thymidine to uracil and thymine and gia and ptosis, and absent tendon re- Department of Pediatrics, 2-deoxy-D-ribose 1-phosphate. ECGF1 flexes in the lower extremities. Meram Medical Faculty, Selcuk mutations cause severe loss of enzyme Plasma lactate levels were slightly University, Konya, Turkey function in patients with MNGIE, result- elevated (18.4 mg/dL [2.04 mmol/L]; ref- (Drs Yavuz, O¨ zel, and Elmaci); ing in very high concentrations of the erence range, 3-12 mg/dL [0.33-1.33 Neuromuscular Research Unit, nucleosides, thymidine, and deoxyuri- mmol/L). Radiography after barium Department of Neurology dine in extracellular fluids.1,2 Altered thy- ingestion showed an excess of gastric (Dr Vissing), and Department of midine and deoxyuridine metabolism has fluid and gastroptosis (Figure 1), but Clinical Genetics, National University Hospital, been proposed to destabilize mitochon- the intestinal passage appeared normal Rigshospitalet, Copenhagen, drial DNA (mtDNA) by interfering with on imaging. Electrophysiological studies 2 Denmark (Ms M. Christensen mtDNA repair and replication. revealed diffuse, mixed sensorimotor and Drs E. Christensen and Despite significant progress in the mo- polyneuropathy. Brainstem auditory Schwartz). lecular characterization of this disease, evoked potential study results were nor-

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©2007 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/28/2021 The patient was treated with intravenous fluids, dom- peridone, and metiamide with good effect on the eme- sis, but in the following year, vomiting got worse, so that she always vomited after meals. After a vomiting episode, the patient developed a generalized tonic-clonic sei- zure. At that time (age 16 years), hemodialysis began 3 times weekly via first femoral, then brachial, catheters. After 2 months of hemodialysis, treatment was shifted to CAPD because CAPD can be performed continu- ously, is better tolerated by most patients, and can be performed outside the hospital. Continuous ambulatory peritoneal dialysis is performed with 1200 mL of 1.5% glucose dialysis fluid every 3 hours. The procedure of emptying and refilling the peritoneum with dialysis fluid takes 10 minutes and is performed by the patient. At the time of publication, the patient had been treated with CAPD for 3 years. Only a few CAPD-related problems occurred during this period (leaking dialysis fluid from the catheter, 1 episode of mild peritonitis, and occasional right shoul- der pain). Magnetic resonance imaging and visual evoked potential and brainstem auditory evoked potential studies were repeated after 2 years of CAPD. Plasma levels of thymidine and deoxyuridine were measured before, during, and after 1 hemodialysis and 4 CAPD Figure 1. Contrast radiograph demonstrating marked gastroptosis. treatments. Thymidine and deoxyuridine levels were also measured in dialysis fluid during 3 CAPD treatments. Samples were injected into a high-performance liquid chromatograph (Alliance model 2690; Waters Corporation, Milford, Mass) equipped with a photodi- ode array detector (model 996; Waters Corporation) operating at 254 nm and recording UV-visible absorption spectra (200-400 nm). All compounds were iden- tified by their retention times and by comparison of their absorption spectra with those of commercially available products.

GENETIC AND METABOLIC FINDINGS

Sequencing of ECGF1 revealed homozygosity for a previously described splice-site mutation (IVS9-1GϾA),1 con- firming the diagnosis of MNGIE. The parents and an asymptomatic sister of the proband were heterozygous for this mutation. Thymidine and deoxyuridine levels were decreased by hemodialysis from 13 and 22 µmol/L before dialysis to 7 and 9 µmol/L after. Continuous ambulatory peritoneal dialysis, however, had no measurable effect on nucleoside levels (Figure 3), and the levels of these metabolites were elevated 100-fold or more compared Figure 2. T2-weighted brain magnetic resonance image of the patient, with concentrations found in healthy subjects (ie, demonstrating diffusely increased signal in the periventricular white matter. Ͻ0.05 µmol/L). Concentrations of the nucleosides in the dialysate were on average one third of plasma levels mal, but visual evoked potential studies showed pro- (Figure 3), and it can be calculated that approximately longed P100 latency. T2-weighted brain magnetic reso- 100 µmol of both thymidine and deoxyuridine were nance imaging showed increased signal affecting the removed daily by dialysis. Thymine and uracil were not periventricular white matter of the frontoparieto- detected in plasma or dialysate at any time. Plasma lac- occipital regions (Figure 2). On suspicion of MNGIE, tate levels ranged between 33 mg/dL [3.66 mmol/L] and we measured plasma thymidine and deoxyuridine levels 52 mg/dL [5.77 mmol/L] during the course of CAPD and sequenced all introns and exons of ECGF1, using treatment and were only decreased by 17% on average methods previously described.3 after each dialysis session.

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©2007 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/28/2021 EFFECT OF DIALYSIS ON SYMPTOMS AND SIGNS Before CAPD End of CAPD During CAPD CAPD Dialysate Before hemodialysis, the patient vomited after every meal. 40 Hemodialysis reduced the frequency of vomiting to once every 2 to 3 days. Continuous ambulatory peritoneal dialysis stopped 30 vomiting completely. If the quantity of dialysis fluid was decreased or dialysis was missed, typically because of a long period of sleeping, the patient consistently devel- 20 oped nausea, weakness, and vomiting. Epigastric pain al-

most disappeared with the treatment, and the anorexia Micromoles per Liter she had before dialysis treatment improved markedly, so 10 that parenteral food supplementation has not been needed. After starting CAPD, her weight increased by 5 kg to 33 0 kg, and she started to menstruate again. Her height re- Thymidine Level Deoxyuridine Level mained unchanged. Her blood pressure also increased with treatment to on average 100/65 mm Hg. Despite the Figure 3. Mean±SE plasma levels of thymidine and deoxyuridine (n=4) progressive nature of the disease, the patient is able to before, during, and after continuous ambulatory peritoneal dialysis (CAPD) climb stairs more easily and walk longer distances than and their mean±SE concentrations in dialysate (n=3) at the end of dialysis. she could 3 years ago before treatment. The level of ophthalmoplegia, the absent tendon reflexes, and findings on brain magnetic resonance imaging and results of vi- High extracellular concentrations of thymidine and de- sual evoked potential and brainstem auditory evoked po- oxyuridine have been proposed to induce nucleoside pool tential studies after 2 years of CAPD treatment did not imbalance in mitochondria that compromise mtDNA rep- change. lication and repair, resulting in a progressive develop- ment of deletions, point mutations, and depletion of mtDNA.2,9 Possible therapies for MNGIE could there- COMMENT fore be enzyme replacement or removal of excess thymidine and deoxyuridine from the extracellular space. The 2 major findings of the present study are that perito- Hemodialysis has previously been studied in 3 patients neal dialysis has a sustained beneficial effect on the se- with MNGIE.5,10 The treatment was only given 1 to 3 times vere gastrointestinal symptoms in MNGIE and that this in each patient, so that the effect of the treatment on the improvement occurred in the face of unchanged extracel- patients’ symptoms could not be assessed. The hemodi- lular levels of thymidine and deoxyuridine. The findings alysis was discontinued in the patients because plasma are important because they represent the first report, to nucleoside levels had returned to pretreatment values 3 our knowledge, of a significant treatment response in hours after dialysis.5 MNGIE and because they clearly indicate that, in addi- Recently, 2 studies have shown partial correction of tion to imbalanced nucleoside pools, the pathogenesis of the excessive nucleoside levels in the plasma of patients MNGIE may be caused by other metabolic factors. with MNGIE by either infusing platelets from healthy sub- Cachexia and early death are characteristic of MNGIE. jects or by performing allogenic stem cell (bone mar- The most debilitating symptoms of MNGIE are the gas- row) transplantation.11,12 These interesting treatments pro- trointestinal manifestations (nausea, anorexia, vomit- vide “proof of principle” that potentially toxic nucleosides ing, abdominal pain, diarrhea) that lead to poor quality can be removed in vivo, but the clinical effect of the treat- of life and severe weight loss. Gastrointestinal symp- ments is unknown. toms develop in nearly all patients with MNGIE, and they We investigated the effect of continued dialysis treat- are often the presenting symptoms, as in our pa- ment on symptoms and nucleoside levels in a patient with tient.1,2,4-6 Most gastrointestinal symptoms in MNGIE stem MNGIE. Stimulated by a very favorable clinical re- from dysmotility of the small intestine. The dysmotility sponse to hemodialysis, the patient was treated with CAPD is in part caused by a pronounced visceral myopathy of for more than 2 years with marked improvements in clini- the external layer of the muscularis propria,6 but an in- cal status. The patient gained weight and could eat with- testinal autonomic neuropathy may also play a role.1 In- out vomiting or getting abdominal pain. She started to testinal dysmotility is likely also the cause of the fre- menstruate again and could walk longer distances than quent occurrence of diverticula in MNGIE, which may before. When dialysis was paused, the patient invari- cause fatal peritonitis.7 ably started to vomit again, thus verifying the treatment The poor quality of life and early death in patients with response. Interestingly, the plasma nucleoside levels were MNGIE call for treatment, but so far, therapy has largely unchanged by CAPD, and basal levels of the nucleo- been supportive, including total parenteral nutrition, pain sides on dialysis treatment were still highly elevated. Di- relief, and treatment of infections. Abdominal pain was alysis removed approximately 100 µmol of thymidine and treated with some success in a patient by celiac plexus deoxyuridine every day, indicating a very high produc- neurolysis.4 Treatment with intravenous immunoglob- tion rate of these metabolites in patients with MNGIE. ulin and corticosteroids has been unsuccessful.8 Since nucleoside levels, as well as urine output, were un-

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©2007 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/28/2021 changed by CAPD, renal excretion of the nucleosides was REFERENCES probably also unchanged. Our findings suggest that CAPD should be consid- 1. Nishino I, Spinazzola A, Hirano M. Thymidine phosphorylase gene mutations in ered as a treatment for patients with MNGIE to alleviate MNGIE, a human mitochondrial disorder. Science. 1999;283:689-692. the debilitating gastrointestinal symptoms. Long-term 2. Hirano M, Lagier-Tourenne C, Valentino ML, Marti R, Nishigaki Y. Thymidine phos- studies are warranted to assess the effect of the treat- phorylase mutations cause instability of mitochondrial DNA. Gene. 2005;354: 152-156. ment on other symptoms in MNGIE. Furthermore, the 3. Vissing J, Ravn K, Danielsen ER, et al. Multiple mtDNA deletions with features of study suggests that symptoms in MNGIE are not solely MNGIE. Neurology. 2002;59:926-929. due to imbalanced nucleoside pools causing mtDNA in- 4. Teitelbaum JE, Berde CB, Nurko S, Buonomo C, Perez-Atayde AR, Fox VL. Di- stability. In keeping with this, deletions and point mu- agnosis and management of MNGIE syndrome in children: case report and re- tations of mtDNA in muscle were lacking in 17 of 18 pa- view of the literature. J Pediatr Gastroenterol Nutr. 2002;35:377-383. 5. Spinazzola A, Marti R, Nishino I, et al. Altered thymidine metabolism due to de- tients with newly diagnosed MNGIE, even though their fects of thymidine phosphorylase. J Biol Chem. 2002;277:4128-4133. 13 muscles were clinically affected. 6. Giordano C, Sebastiani M, Plazzi G, et al. Mitochondrial neurogastrointestinal encephalomyopathy: evidence of mitochondrial DNA depletion in the small intestine. Gastroenterology. 2006;130:893-901. Accepted for Publication: October 13, 2006. 7. Hirano M, Nishigaki Y, Marti R. Mitochondrial neurogastrointestinal encephalo- Correspondence: John Vissing, MD, PhD, Neuromus- myopathy (MNGIE): a disease of two genomes. Neurologist. 2004;10:8-17. cular Clinic, Department of Neurology 2082, National 8. Bedlack RS, Vu T, Hammans S, et al. MNGIE neuropathy: five cases mimicking University Hospital, Rigshospitalet, Blegdamsvej 9, DK- chronic inflammatory demyelinating polyneuropathy. Muscle Nerve. 2004; 29:364-368. 2100 Copenhagen, Denmark ([email protected]). 9. Song S, Wheeler LJ, Mathews CK. Deoxyribonucleotide pool imbalance stimu- Author Contributions: Study concept and design: Yavuz lates deletions in HeLa Cell mitochondrial DNA. J Biol Chem. 2003;278:43893- and Vissing. Acquisition of data: O¨ zel, M. Christensen, and 43896. Elmaci. Analysis and interpretation of data: M. Chris- 10. la Marca G, Malvagia S, Casetta B, et al. Pre- and post-dialysis quantitative dos- tensen, E. Christensen, Schwartz, and Vissing. Drafting age of thymidine in urine and plasma of a MNGIE patient by using HPLC-ESI-MS/MS. J Mass Spectrom. 2006;41:586-592. of the manuscript: Vissing. Critical revision of the manu- 11. Lara MC, Vais B, Illa I, et al. Infusion of platelets transiently reduces nucleoside script for important intellectual content: M. Christensen, overload in MNGIE. Neurology. 2006;67:1461-1463. E. Christensen, Schwartz, and Vissing. Obtained fund- 12. Hirano M, Marti R, Casali C, et al. Allogenic stem cell transplantation corrects ing: Vissing. Administrative, technical, and material sup- biochemical derangements in MNGIE. Neurology. 2006;67:1458-1460. ¨ 13. Kocaefe YC, Erdem-O¨ zdamar S, Sivri HS, Coskun T, Tan E, O¨ zgu¨c M. Compre- port: Yavuz, Ozel, E. Christensen, Schwartz, Elmaci, and hensive analysis reveals distinct mtDNA features in Mitochondrial Neurogastro- Vissing. Study supervision: Vissing. intestinal Encephalomyopathy Syndrome (MNGIE) [abstract]. Neuromuscul Disord. Financial Disclosure: None reported. 2006;16(suppl 1):S57-S58.

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