Muscle Cramps in Cirrhosis: A Moving Target

Imatinib therapy of chronic myeloid leukemia significantly reduces carnitine cell intake, resulting in adverse events

OBJECTIVE

A prominent, safe and efficient therapy for patients with chronic myeloid leukemia (CML) is inhibiting oncogenic protein BCR::ABL1 in a targeted manner with imatinib, a tyrosine kinase inhibitor. A substantial part of patients treated with imatinib report skeletomuscular adverse events affecting their quality of life. OCTN2 membrane transporter is involved in imatinib transportation into the cells. At the same time, the crucial physiological role of OCTN2 is cellular uptake of carnitine which is an essential co-factor for the mitochondrial β-oxidation pathway. This work investigates the impact of imatinib treatment on carnitine intake and energy metabolism of muscle cells.

METHODS

HTB-153 (human rhabdomyosarcoma) cell line and KCL-22 (CML cell line) were used to study the impact of imatinib treatment on intracellular levels of carnitine and vice versa. The energy metabolism changes in cells treated by imatinib were quantified and compared to changes in cells exposed to highly specific OCTN2 inhibitor vinorelbine. Mouse models were used to test whether in vitro observations are also achieved in vivo in thigh muscle tissue. The analytes of interest were quantified using a Prominence HPLC system coupled with a tandem mass spectrometer.

RESULTS

This work showed that through the carnitine-specific transporter OCTN2, imatinib and carnitine intake competed unequally and intracellular carnitine concentrations were significantly reduced. In contrast, carnitine preincubation did not influence imatinib cell intake or interfere with leukemia cell targeting. Blocking the intracellular supply of carnitine with imatinib significantly reduced the production of most Krebs cycle metabolites and ATP. However, subsequent carnitine supplementation rescued mitochondrial energy production. Due to specific inhibition of OCTN2 activity, the influx of carnitine was blocked and mitochondrial energy metabolism was impaired in muscle cells in vitro and in thigh muscle tissue in a mouse model.

CONCLUSIONS

This preclinical experimental study revealed detrimental effect of imatinib on carnitine-mediated energy metabolism of muscle cells providing a possible molecular background of the frequently occurred side effects during imatinib therapy such as fatigue, muscle pain and cramps.

Muskelzuckungen und Muskelkrämpfe – Differenzialdiagnosen und elektrophysiologische Diagnostik

Muskelzuckungen und -krämpfe sind Beschwerden, die vom harmlosen Symptom bis hin zu Symptomen einer schwerwiegenden neurologischen Erkrankung reichen können. Eine ausführliche Anamnese, gründliche neurologische Untersuchung und elektrophysiologische Untersuchungen ermöglichen die Unterscheidung der verschiedenen Ätiologien. In diesem Artikel werden verschiedene Ursachen unter Berücksichtigung deren Definition, der elektrophysiologisch zugrunde liegenden Phänomene und deren differenzialdiagnostischer Einordnung dargestellt.

Effectiveness of 4-Week Oral Taurine Treatment for Muscle Cramps in Patients with Liver Cirrhosis: A Single-Arm Pilot Study

PURPOSE

Painful muscle cramps are a common complication in liver cirrhosis patients, and no effective treatment is available. This pilot study aimed to evaluate whether taurine supplementation improves muscle cramps in Korean cirrhotic patients.

MATERIALS AND METHODS

Ten cirrhotic patients who experienced muscle cramps one or more times/week were enrolled in this prospective single-arm study and administered with an oral taurine solution (1 g/50 mL) thrice a day for 4 weeks. Taurine was discontinued for the subsequent 4 weeks. The frequency and intensity of muscle cramps were evaluated using a questionnaire at weeks 0, 2, 4, 6, and 8 after the start of treatment.

RESULTS

At baseline, the median frequency of muscle cramps was six times/week, and all patients had severe pain. Muscle cramp scores (frequency×intensity) decreased in seven patients by weeks 4 and 8 after treatment initiation. Compared to baseline muscle cramp scores [median 21, interquartile range (IQR): 8-84], median muscle cramp scores were lower at week 4 (6.5, IQR: 3-12, p=0.126) and week 8 (5, IQR: 1.5-56, p=0.066). All five patients whose baseline plasma taurine levels were below the normal limit showed increased taurine levels at week 4; 60% of them experienced improvements in their muscle cramps. Of the five patients with normal or higher taurine levels, 80% experienced an improvement in symptoms at week 4. The safety and tolerability of the 4-week taurine therapy were excellent.

CONCLUSION

Oral taurine therapy for 4 weeks improved muscle cramps safely in cirrhotic patients.

Clinical features of liver cirrhosis patients with muscle cramping: a multicenter study

BACKGROUND

There has been a small number of reports mention the clinical features including quality of life (QOL) in liver cirrhosis (LC) patients with muscle cramping and therapeutic efficacy for muscle cramping. We evaluated clinical features of muscle cramping and treatments in such patients.

PATIENTS AND METHODS

Two-hundred and eighty-nine LC outpatients (70.6 ± 10.5 years old; male: female = 149: 140) were questioned regarding the presence or absence of muscle cramps within the last 3 months, including frequency, severity of related pain using a visual analogue scale, cramp locations, time of day, duration, sleep disturbance, daily activity decline, and being conscious of QOL decline. At the next hospital-visit, 3 or 4 months later, the subjects, who treated with medical intervention, received the same questionnaire.

RESULTS

Patients with muscle cramps (n = 160) included a higher percentage of females (53.8 vs. 41.9%, P = 0.045), worse Child-Pugh score (5: 6: 7: 8: 9: 10 = 91: 36: 15: 10: 4: 4 vs. 85: 25: 12: 5: 0: 2, P = 0.043) and lower platelet count (10.2 ± 4.7 vs. 11.8 ± 5.0 × 104/µl, P = 0.006) as compared to those without cramps (n = 129). Of the 160 with cramping, 82 (51.3%), received treatment with several types of medication, with l-carnitine the most administered drug (n = 66: 80.5%), and those also showed a tendency to complain about muscle cramps at night, sleep disturbance, reduced daily activity, and being conscious of QOL decline (each P < 0.01). We observed that frequency, visual analogue scale, sleep disturbance, daily activity, duration of muscle cramping, and being conscious of QOL decline were improved after the intervention (each P < 0.001, respectively).

CONCLUSION

Intervention for muscle cramping improves total QOL in LC patients with such symptom.

Impact of L-carnitine on imatinib-related muscle cramps in patients with gastrointestinal stromal tumor

Introduction Muscle cramps constitute one of the leading adverse events of imatinib, the standard first-line treatment for advanced gastrointestinal stromal tumor (GIST). This study aims to assess the impact of L-carnitine on relieving cramps in patients with GIST taking imatinib. Materials and methods We reviewed our prospective database for patients with GIST who took L-carnitine (500-mg tablet, 2-3 times daily) for muscle cramps in Asan Medical Center. The assessment tool included severity by the numeric rating scale (NRS), frequency, duration of cramps, and questionnaire for the disturbance in basic activities of daily living (ADL), instrumental ADL (iADL), outdoor activity, or sleeping before and after L-carnitine treatment. Results We examined 42 patients [median age: 60 (range: 17-81) years; males, 52.4%] who received L-carnitine for cramps on NRS ≥ 4 intensity during 2016-2017. In 83.3% of patients (n = 35), the NRS score declined to <4 points, with 8 patients (19.0%) experiencing complete disappearance of symptoms [median response time: 10 (range: 2-30) days]. Moreover, the median duration of each episode and frequency decreased from 5 to 2 min and from 30 to 3 times per month (P < 0.001), respectively. We observed substantial improvement in all quality-of-life aspects after L-carnitine (ADL, 73.2%-14.6%; iADL, 73.2%-17.1%; sleeping, 78.0%-22.0%; outdoor activity, 68.3%-17.1%; P < 0.001). ConclusionL-carnitine could effectively relieve imatinib-related muscle cramps in patients with GIST. Accordingly, a randomized phase 3 study is currently ongoing (NCT03426722).

Can L-carnitine supplementation and exercise improve muscle complications in patients with liver cirrhosis who receive branched-chain amino acid supplementation?

BACKGROUND

The aim of this study was to elucidate the efficacy of the combination of L-carnitine and exercise, reported to prevent muscle wasting, for muscle complications (function, volume, and cramping) in patients with liver cirrhosis (LC) who received branched-chain amino acid supplementation.

MATERIALS AND METHODS

From December 2017 to April 2018, 18 patients with LC who had been given branched-chain amino acid granule supplementation (12.45 g/day) were enrolled (mean age 68.4±10.8 years; 10 males and eight females; Child-Pugh A : B=9 : 9). After evaluating the average number of daily steps, oral L-carnitine supplementation (1000 mg/day) and additional exercise (plus 2000 steps/day) were added for 6 months. Every 4 weeks, a pedometer, a hand dynamometer, ergometer, and bioelectrical impedance analysis were used to evaluate daily steps, muscle function and muscle volume, and muscle cramps were recorded using a numerical rating scale.

RESULTS

Average steps and serum levels of total and free carnitine were increased from before treatment to the final measurement (1883.5±1211.6 vs. 3165.1±1800.0/day, 62.6±16.5 vs. 110.9±28.6 μmol/l, and 47.7±15.2 vs. 83.2±21.5 μmol/l, respectively; P<0.01), whereas there were no significant changes in the ratios of handgrip strength, leg strength, and muscle volume after 6 months [1.00±0.13 (P=0.991), 1.07±0.13 (P=0.073), and 0.992±0.036 (P=0.390), respectively]. However, the frequency of complaints of muscle cramping was reduced as compared with the start of therapy (baseline, 3 months, and 6 months: 6.3±4.8, 3.1±3.3, and 2.1±2.0, respectively) (P=0.025, Holm's method), whereas numerical rating scale did not show any significant improvement.

CONCLUSION

L-Carnitine may have an important role for prevention of muscle wasting and reducing the frequency of muscle cramping.

Pilot study of orphenadrine as a novel treatment for muscle cramps in patients with liver cirrhosis

Background and aims

Muscle cramps markedly affect the quality of life in cirrhotic patients with no available highly effective treatment. The aim of this study was to assess the safety and efficacy of orphenadrine in the treatment of muscle cramps in cirrhotic patients.

Methods

The study enrolled 30 liver cirrhosis patients complaining of frequent muscle cramps (≥3 per week), who were randomized to receive either orphenadrine 100 mg or calcium carbonate 500 mg twice daily as a control for one month. Severity, frequency, and duration of the muscle cramps were assessed before and after treatment as well as recurrence after washout of the drug for two weeks. Side effects were recorded.

Results

One month after treatment with orphenadrine; the frequency of muscle cramps decreased significantly to 0.6 ± 0.74 per week compared to 12.53 ± 6.01 at baseline (p < 0.001), the duration of muscle cramps decreased from 1 min to 0.1 min after treatment (p < 0.001). The pain score improved significantly from a score of 8/10 to 0/10 (p < 0.001). The side effects were few, such as dry mouth, drowsiness, and nausea, with no significant difference between their occurrences in the two groups.

Conclusion

Orphenadrine is safe and effective in treatment of muscle cramps in patients with liver cirrhosis.