Treatment with L-citrulline in patients with post-polio syndrome: study protocol for a single-center, randomised, placebo-controlled, double-blind trial

BACKGROUND

Post-polio syndrome (PPS) is a condition that affects polio survivors years after recovery from an initial acute infection by the Poliomyelitis virus. Most often, patients who suffered from polio start to experience gradual new weakening in muscles, a gradual decrease in the size of muscles (muscle atrophy) and fatigue years after the acute illness. L-citrulline is known to change muscular metabolism synthesis by raising nitric oxide (NO) levels and increasing protein synthesis. This investigator-initiated, randomised, placebo-controlled, double-blind, trial aims to demonstrate that L-citrulline positively influences muscle function and increases muscular energy production in patients with PPS.

METHODS/DESIGN

Thirty ambulant PPS patients will be recruited in Switzerland. Patients will be randomly allocated to one of the two arms of the study (placebo:verum 1:1). After a 24-week run-in phase to observe natural disease history and progression, participants will be treated either with L-citrulline or placebo for 24 weeks. The primary endpoint is change in the 6-min Walking Distance Test. Secondary endpoints will include motor function measure, quantitative muscle force, quantitative muscle magnetic resonance imaging and magnetic resonance spectroscopy and serum biomarker laboratory analysis DISCUSSION: The aim of this phase IIa trial is to determine if treatment with L-citrulline shows a positive effect on clinical function and paraclinical biomarkers in PPS. If treatment with L-citrulline shows positive effects, this might represent a cost-efficient symptomatic therapy for PPS patients.

TRIAL REGISTRATION

ClinicalTrial.gov, ID: NCT02801071 . Registered on 6 June 2016.

[Polio, late effects and post-polio]

Approximately 7,000 Danes are still living with sequelae after surviving an acute polio infection. Late effects of polio include deformities, arthrosis and overloaded muscles. In the long run polio patients are at risk of having a further decrease of muscle function and a wide variety of other symptoms, a condition called post-polio syndrome (PPS). Treatment of PPS is in general symptomatic. Recently it has been shown that treatment with intravenous immunoglobulin may have an effect on pain, tiredness and walking distance. Patients with prior polio have an increase in morbidity and mortality, and may be more sensitive to a variety of medicine.

Intravenous immunoglobulin treatment of the post-polio syndrome: sustained effects on quality of life variables and cytokine expression after one year follow up

BACKGROUND

Expression of inflammatory cytokines in cerebrospinal fluid (CSF) has led to the hypothesis of intrathecal chronic inflammation to explain the denervation observed in post-polio syndrome (PPS). It has been shown that therapy with intravenous immunoglobulin (IVIG) improves physical performance and dampens down the inflammatory process at 6 months in PPS patients. We here examined the effects of IVIG on cytokine expression and clinical outcome one year after IVIG treatment.

METHODS

From a previous study with 135 PPS patients included, 41 patients were further evaluated before un-blinding for one year (21 placebo and 20 treated with IVIG, Xepol® 50 mg/ml), and were assessed for clinical variables by performing the Short Form-36 survey (SF-36) questionnaire assessment, the 6 minute walk distance test (6MWT) and registering pain level by Visual Analogue Scale (VAS) after IVIG treatment. A separate cohort of 37 PPS patients went through lumbar puncture (LP) at baseline and 20 patients, treated with IVIG, repeated the LP one year later. Thirty patients affected with other neurological diseases (OND) were used as control group. Inflammatory cytokines TNF, TGFβ, IFNγ, IL-23, IL-13 and IL-10 were measured in blood cells and CSF cells with RT-PCR.

RESULTS

Scores of the physical components of SF-36 were significantly higher at the one year follow up time-point in the IVIG-treated patients when compared to baseline as well as to the control subjects. Pain VAS score and 6MWT improved significantly in the IVIG-treated patients when compared with baseline Relative expression of TNF and IFN-γ in both PBMCs and CSF from PPS patients were increased compared to OND subjects at baseline (p < 0.05). One year after IVIG-treatment a decreased expression of IFN-γ and IL23 was found in CSF of PPS patients, while anti-inflammatory IL-13 was increased (p < 0.05).

CONCLUSIONS

IVIG has effects on relevant QoL variables and inflammatory cytokines up to one year in patients with PPS. This gives a basis for scheduling IVIG in upcoming trials with this therapy.

Treatment for postpolio syndrome

BACKGROUND

Postpolio syndrome (PPS) may affect survivors of paralytic poliomyelitis and is characterised by a complex of neuromuscular symptoms leading to a decline in physical functioning. The effectiveness of pharmacological treatment and rehabilitation management in PPS is not yet established.

OBJECTIVES

To review systematically the effects of any treatment for PPS compared to placebo, usual care or no treatment.  

SEARCH STRATEGY

We searched the following databases on 1 October 2010: Cochrane Neuromuscular Disease Group Specialized Register, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, PsycINFO and CINAHL Plus from inception to September 2010.

SELECTION CRITERIA

Randomised and quasi-randomised trials of any form of pharmacological or non-pharmacological treatment for people with PPS. The primary outcome was self-perceived activity limitations and secondary outcomes were muscle strength, muscle endurance, fatigue, pain and adverse events.

DATA COLLECTION AND ANALYSIS

Two authors independently selected eligible studies, assessed risk of bias and extracted data.

MAIN RESULTS

Nine pharmacological (modafinil, intravenous immunoglobulin, pyridostigmine, lamotrigine, amantadine, prednisone) and three non-pharmacological (muscle strengthening, rehabilitation in a warm climate (i.e. temperature ± 25°C, dry and sunny) and a cold climate (i.e. temperature ± 0°C, rainy or snowy), static magnetic fields) studies were included in this review. None of the included studies was completely free from any risk of bias and the most prevalent risk of bias was lack of blinding.There is moderate quality evidence that intravenous immunoglobulin has no beneficial effect on activity limitations and there is inconsistency in the evidence for effectiveness on muscle strength and pain. Results of one trial provide very low quality evidence that lamotrigine might be effective in reducing pain and fatigue, resulting in fewer activity limitations. Data from two single trials suggest that muscle strengthening of thumb muscles (very low quality evidence) and static magnetic fields (moderate quality evidence) are beneficial for improving muscle strength and pain, respectively, with unknown effects on activity limitations. Finally, there is evidence varying from very low quality to high quality that modafinil, pyridostigmine, amantadine, prednisone and rehabilitation in a warm or cold climate are not beneficial in PPS.

AUTHORS' CONCLUSIONS

Due to insufficient good quality data and lack of randomised studies it is impossible to draw definite conclusions on the effectiveness of interventions for PPS. Results indicate that IVIG, lamotrigine, muscle strengthening exercises and static magnetic fields may be beneficial but need further investigation.

Post-polio syndrome patients treated with intravenous immunoglobulin: a double-blinded randomized controlled pilot study

Post-polio syndrome (PPS) is characterized by new muscle weakness, atrophy, fatigue and pain developing several years after the acute polio. Some studies suggest an ongoing inflammation in the spinal cord in these patients. From this perspective, intravenous immunoglobulin (IvIg) could be a therapeutic option. We performed a double-blinded randomized controlled pilot study with 20 patients to investigate the possible clinical effects of IvIg in PPS. Twenty patients were randomized to either IvIg 2 g/kg body weight or placebo. Primary endpoints were changes in pain, fatigue and muscle strength 3 months after treatment. Surrogate endpoints were changes in cerebrospinal fluid (CSF) cytokine levels. Secondary endpoints were pain, fatigue and isometric muscle strength after 6 months. Patients receiving IvIg reported a significant improvement in pain during the first 3 months, but no change was noted for subjective fatigue and muscle strength. CSF levels of tumour necrosis factor-alpha (TNF-alpha) were increased compared with patients with non-inflammatory neurological disorders. In conclusion, in this small pilot study no effect was seen with IvIg treatment on muscle strength and fatigue, however IvIg treated PPS patients reported significantly less pain 3 months after treatment. TNF-alpha was increased in the CSF from PPS patients. The results are promising, but not conclusive because of the low number of patients studied.

Successful treatment of a postpolio tinnitus with type a botulinum toxin

OBJECTIVES/HYPOTHESIS

Objective tinnitus is a symptom often observed in patients with chronic hyperactivity of masticatory muscles.

METHODS

We report here the unusual case of a 63-year-old woman who developed a distressing tinnitus related to contractions of reinnervated masticatory muscles. This reinnervation process was caused by a postpolio syndrome that gave rise to an acoustic resonance phenomenon transmitted to the middle ear as an audible sound.

RESULTS

The tinnitus was successfully treated with electromyography-guided intramuscular injections of type A botulinum toxin.

CONCLUSION

The intramuscular injection of botulinum toxin was found to be effective in relieving severe and disabling postpolio tinnitus.

Randomized controlled trial of modafinil for the treatment of fatigue in postpolio patients

The purpose of this study was to test whether modafinil is effective in alleviating the symptoms of fatigue in postpolio patients, because it has been helpful for such symptoms in other neurologic disorders. Using a double-blind, randomized, placebo-controlled cross-over design, 14 postpolio patients with moderate to severe fatigue were assigned to receive modafinil or placebo first. Piper Fatigue Scale, Epworth Sleepiness Scale, digit span, and reaction time tests were done at baseline and then at weekly intervals. The Piper Fatigue Scale scores improved by 27 +/- 40% (mean +/- SD) following modafinil and by 43 +/- 36% following placebo. Scores for most of the other tests did not change during the study. Therefore, we conclude that modafinil was not effective in alleviating the symptoms of fatigue in postpolio patients.

Effects of lamotrigine on the symptoms and life qualities of patients with post polio syndrome: a randomized, controlled study

The aim of this study is to find out if lamotrigine gives symptomatic relief and enhances quality of life in patients with post-polio syndrome. Thirty patients were randomly assigned to receive or not to receive lamotrigine treatment. Lamotrigine at a daily dose of 50-100 mg was given to the fifteen patients, and fifteen patients were used as the control group. Interventional advice and home exercises were given to all of the patients. Clinical assessments were made at baseline and repeated at the second and fourth weeks by the physician who was unaware of medication. The severity of pain, fatigue and muscle cramps were rated on a visual analogue scale. Health-related quality of life was measured using the Nottingham Health Profile. The patient's perceived level of fatigue was assessed using Fatigue Severity Scale. Comparing to the baseline values, statistically significant improvements were obtained in the mean scores of VAS, NHP and FSS at two weeks and four weeks in the patients on lamotrigine. No significant improvements were reported in the control group. These preliminary results indicate that lamotrigine relieves the symptoms and improves the life qualities of patients with post polio syndrome.

Pyridostigmine in postpolio syndrome: no decline in fatigue and limited functional improvement

OBJECTIVES

To investigate the effect of pyridostigmine on fatigue, physical performance, and muscle function in subjects with postpoliomyelitis syndrome.

METHODS

67 subjects with increased fatigue and new weakness in one quadriceps muscle showing neuromuscular transmission defects, were included in a randomised, double blind, placebo controlled trial of 60 mg pyridostigmine four times a day for 14 weeks. Primary outcome was fatigue (on the "energy" category of the Nottingham health profile). Secondary outcomes included two minute walking distance and quadriceps strength and jitter. Motor unit size of the quadriceps was studied as a potential effect modifier. The primary data analysis compared the changes from baseline in the outcomes in the last week of treatment between groups.

RESULTS

31 subjects treated with pyridostigmine and 31 subjects treated with placebo completed the trial. No significant effect of pyridostigmine was found on fatigue. The walking distance improved more in the pyridostigmine group than in the placebo group (by 7.2 m (6.0%); p<0.01). Subgroup analysis showed that a significant improvement in walking performance was only found in subjects with normal sized motor units. Quadriceps strength improved more in the pyridostigmine group than in the placebo group (by 6.7 Nm (7.2%); p = 0.15). No effect of pyridostigmine was found on jitter.

CONCLUSIONS

Pyridostigmine in the prescribed dose did not reduce fatigue in subjects with postpoliomyelitis syndrome. However, it may have a limited beneficial effect on physical performance, especially in subjects with neuromuscular transmission defects in normal sized motor units.

A multicenter, randomized, double-blinded trial of pyridostigmine in postpolio syndrome

BACKGROUND

Postpoliomyelitis syndrome (PPS) is likely due to degeneration and dysfunction of terminal axons of enlarged postpolio motor units. Age-related decline in growth hormone and insulin-like growth factor (IGF-I) may be a contributing factor. Neuromuscular junction abnormalities and decreased IGF-I levels may respond to the anticholinesterase pyridostigmine, with consequent improvement in strength, fatigue, and quality of life.

OBJECTIVES

To determine the effect of pyridostigmine in PPS on health-related quality of life, isometric muscle strength, fatigue, and serum IGF-I levels; and to assess the safety of pyridostigmine in PPS.

METHODS

The study was a multicenter, randomized, double-blinded, placebo-controlled trial of a 6-month course of pyridostigmine 60 mg three times per day in 126 PPS patients. The primary data analysis compared mean changes of outcomes between treatment and control groups at 6 months using an intention to treat approach. Secondary analyses included a comparison of outcomes at 6 and 10 weeks, and in compliant patients.

RESULTS

The study showed no significant differences in pyridostigmine and placebo-treated patients with regard to changes in quality of life, isometric strength, fatigue, and IGF-I serum levels at 6 months in the primary analysis and in compliant patients. There were no differences in outcomes at 6 and 10 weeks between groups. However, very weak muscles (1 to 25% predicted normal at baseline) were somewhat stronger (p = 0.10, 95% CI of difference -9.5 to 73.3%), and in compliant patients IGF-I was somewhat increased (p = 0.15, 95% CI of difference -6.4 to 44.8 ng/mL) at 6 months with the medication. Pyridostigmine was generally well tolerated.

CONCLUSIONS

This study showed no significant differences between pyridostigmine and placebo-treated PPS patients on measures of quality of life, isometric strength, fatigue, and serum IGF-I.

Carrell-Krusen Symposium invited lecture. Clinical trials in motor neuron diseases

Although there is no truly effective disease-specific therapy for any of the motor neuron diseases, rapid progress in our understanding of the pathophysiology of some of these disorders is being made. In addition to progress in neuroscience, clinical trials of agents that appear to slow the progress of at least one of these diseases, amyotrophic lateral sclerosis, are beginning to show promising results. The first clinical trials in spinal muscular atrophy are currently underway. A number of other developments have raised the quality of clinical trials, which should improve their productivity and efficiency in the future.

Effects of oral supplementation of coenzyme Q10 on 31P-NMR detected skeletal muscle energy metabolism in middle-aged post-polio subjects and normal volunteers

The effects of oral supplementation of 100 mg coenzyme Q10 (CoQ10) for 6 months on muscle energy metabolism during exercise and recovery were evaluated in middle-aged post-polio (n = 3) and healthy subjects (n = 4) by the use of phosphorus-31 nuclear magnetic resonance spectroscopy. The metabolic response to isometric plantar flexion at 60% of maximal voluntary contraction force (MVC) for 1.5 min was determined in gastrocnemius muscles before, after 3- (3MO) and 6-month (6MO) of CoQ10 supplementation. The MVC of plantar flexion was unchanged following CoQ10 supplementation. The resting Pi/PCr ratio in gastrocnemius muscles of all subjects decreased after 3MO- and 6MO-CoQ10 (P < 0.05). The post-polio individuals showed a progressive decrease in this ratio, while less pronounced changes were observed in the control subjects. Similarly, the post-polio individuals showed a lower Pi/PCr ratio at the end of 60% MVC in both 3MO- and 6MO-CoQ10, whereas no change in the ratio was observed in the control subjects. A less pronounced decrease in muscle pH was observed at the end of 60% MVC in both 3MO- and 6MO-CoQ10 in the post-polio individuals, but not in the control subjects. No systematic difference in end-exercise ATP was observed between the three phases in both groups. The half-time of recovery for PCr decreased in all subjects after 6MO-CoQ10 supplementation (P < 0.05). The results suggest that CoQ10 supplementation affects muscle energy metabolism in post-polio individuals to a greater extent than in control subjects. The mechanism for this effect is not clear, but may involve an effect of CoQ10 on peripheral circulation in the calf muscles, its action in mitochondrial oxidative phosphorylation and/or its antioxidant potential.

Bromocriptine in the treatment of post-polio fatigue: a pilot study with implications for the pathophysiology of fatigue

Fatigue is the most commonly reported and most disabling of all post-polio sequelae (PPS). Bromocriptine mesylate (Parlodel) was employed in a placebo-controlled trial in five survivors of paralytic polio who continued to report moderate to severe daily fatigue after complying with the conservative treatments prescribed for PPS. Placebo was given for 4 wk followed by increasing doses of bromocriptine mesylate, administered at 12:00 pm for 28 days, which reached a total dose of 12.5 mg/day. Three subjects reported marked symptom improvement on bromocriptine but not on placebo. Their reported difficulty with attention, concentration, word finding, mind wandering, memory, thinking clearly, and fatigue on awakening was significantly negatively correlated with days on bromocriptine but not with days on placebo. Before the drug trial began, responders had clinically impaired performance on neuropsychologic tests of attention and information processing speed, more than twice as many hyperintensities on magnetic resonance imaging of the brain, abnormally low fasting adrenocorticotropic hormone levels, and nearly double the mean plasma prolactin level compared with nonresponders. The implications of these findings for the pathophysiology of fatigue are discussed. A double-blind, placebo-controlled, multicenter study will be needed to confirm bromocriptine's efficacy in treating attentionally and neurophysiologically impaired polio survivors whose severe and disabling fatigue does not respond to conservative therapies.

An open trial of pyridostigmine in post-poliomyelitis syndrome

BACKGROUND

One of the major symptoms of postpoliomyelitis syndrome (PPS) is disabling generalized fatigue. Subjects with PPS also report muscle fatiguability and display electrophysiologic evidence of anticholinesterase-responsive neuromuscular junction transmission defects, suggesting that anticholinesterase therapy may be useful in the management of disabling fatigue.

METHODS

We initiated an open trial of the oral anticholinesterase pyridostigmine, up to 180 mg per day, in 27 PPS patients with generalized fatigue and muscle fatiguability. Response to pyridostigmine was assessed with the Hare fatigue scale, the modified Barthel index for activities of daily living, and a modified Klingman mobility index.

RESULTS

Two patients could not tolerate the medication. After one month of therapy, 16 patients (64%) reported a reduction in fatigue on the Hare fatigue scale; three of 16 showed improvement on the modified Barthel index for activities of daily living, and two of 16 experienced improvement on a modified Klingman mobility index. Pyridostigmine responders were significantly more fatigued than non-responders on the pre-treatment Hare score, but were not significantly different with regard to age, sex, age at acute poliomyelitis, or severity of acute poliomyelitis.

CONCLUSIONS

Pyridostigmine may be useful in the management of fatigue in selected patients with PPS. Response to pyridostigmine may be predicted by severity of pre-treatment fatigue.

A double-blind, placebo-controlled trial of amantadine for the treatment of fatigue in patients with the post-polio syndrome

Because amantadine has been shown to reduce fatigue in patients with multiple sclerosis, we performed a double-blind, placebo-controlled study to assess its efficacy in the disabling symptom of post-polio fatigue. Twenty-three patients completed six weeks of therapy. Fatigue was measured by the patients using visual analogue scales (twice per day) and numerical fatigue severity scales (once per week) and by overall impression (at end of therapy). Formal neuropsychological testing and serum drug levels were performed to assess compliance. On all measures, no significant difference was found between treatment and placebo groups. Fifty-four percent of patients given amantadine and 43% given placebo reported a decrease in fatigue; however, the visual analogue scales and fatigue severity scales failed to reflect any improvement. Several patients in the treatment group elected to continue amantadine therapy after the study was completed. Our findings suggest that amantadine is not significantly better than placebo in reducing the sensation of fatigue in post-polio syndrome, and that the measures we employed were insensitive to capture the subjective response experienced by a few patients.

Postpolio syndrome--response to deprenyl (selegiline)

Two patients with postpolio syndrome are presented. The first case developed mild Parkinson's syndrome, for which she was treated with a levodopa/carbidopa combination followed by the institution of deprenyl. An unexpected improvement in the symptoms of postpolio syndrome was noted. The second patient who was unaffected by Parkinson's syndrome was started on deprenyl alone and reported a similar improvement in symptomatology.

Anticholinesterase-responsive neuromuscular junction transmission defects in post-poliomyelitis fatigue

Disabling generalized fatigue and muscle fatiguability are common features of post-poliomyelitis syndrome (PPS). In 17 fatigued PPS patients, we measured jitter on stimulation single-fiber electromyography (S-SFEMG) for at least 3.5 min before and after i.v. injection of 10 mg edrophonium. We observed reduction in jitter (defined as a significant difference in jitter means before and after edrophonium, unpaired t-test P < 0.05) in 7 patients, no change in 8, and a significant increase in 2 patients. Blinded to their edrophonium results, the 17 patients were treated with pyridostigmine 180 mg/day for 1 month, with a subjective improvement of fatigue in 9 patients, and with a significant reduction in mean Hare fatigue scores in the entire group of 17 patients (pre = 2.71, and post = 1.71; Wilcoxan signed rank sum test, P < 0.05). Edrophonium-induced reduction of jitter on S-SFEMG was significantly associated with pyridostigmine-induced subjective improvement of fatigue (Fisher's exact test, P < 0.04). A significant reduction in fatigue with pyridostigmine was observed only in the 7 patients who experienced a significant reduction in jitter with edrophonium (Wilcoxan signed rank sum test, P = 0.03). In addition, the 9 pyridostigmine responders experienced a significant reduction in jitter means pre- and post-edrophonium (100% vs. 88%, Bonferroni corrected, P < 0.01). We conclude that neuromuscular transmission as measured by jitter on S-SFEMG can improve with edrophonium in a proportion of PPS patients, and that generalized fatigue and muscle fatiguability in some patients with PPS may be due to anticholinesterase-responsive NMJ transmission defects.

[A trial of cronassial use in late postpoliomyelitis syndrome]

The results are presented of treatment with gangliosides (Cronassial) in 5 patients with late postpoliomyelitis syndrome. Clinical and electrophysiological examination were done before and after three months of treatment. Only subjective improvement was found. A year-long follow-up failed to fluid progression of the signs and symptoms that, formerly, were progressing slowly. It seems that Cronassial administration (in larger doses and for a longer time) is justified in patients with peripheral motor neuron lesion.