Entacapone improves complex movement performance in patients with Parkinson’s disease

[The role of inhibitors of COMT and MAO-B in the therapy of Parkinson's disease]

Inhibitors of COMT and MAO-B are well established in the pharmacotherapy of Parkinson's disease (PD). MAO-B inhibitors are used as monotherapy as well as in combination with levodopa, whereas COMT inhibitors exert their effects only in conjungtion with levodopa. Both classes of compounds prolong the response duration of levodopa and optimise its clinical benefit. As a result, the ON-times are prolonged significantly. In the past, MAO-B inhibitors were also adminstered for neuroprotection; however, despite convincing scientific reasoning in support of neuroprotective effects, these could not be substantiated in clinical studies performed so far.

Kinesiology training in patients with Parkinson's disease: results of a pilot study

Complementary therapies are an essential component of the treatment of patients with Parkinson's disease. They aim to ameliorate disease symptoms in conjunction with dopamine substitution. Kinesiology trains about the effective use of physical, mental and emotional skills. Objectives of this pilot study were to demonstrate the efficacy of a standardised kinesiology programme in 20 patients with Parkinson's disease. They were on a stable drug regimen during the whole trial. Ten patients received two kinesiology sessions per week over a 6-week lasting interval. The remaining ten patients were only followed over the same time period without any kinesiology training. We scored disease symptoms, tested cognition and assessed instrumental movement performance at baseline and study end. Kinesiology improved disease symptoms, cognitive abilities and execution of simple but not complex movement series. We show a certain value of a standardised kinesiology programme as adjunct, complementary therapeutic approach in patients with Parkinson's disease.

A secret that underlies Parkinson's disease: The damaging cycle

Parkinson's disease (PD) is a movement disorder, and its common characteristics include the loss of dopaminergic neurons and the accumulation of a special type of cytoplasmic inclusions called Lewy bodies in the substantia nigra pars compacta, which are more prevalent in the elderly. However, the pathophysiology of PD is still elusive. In this review, we summarized five common factors involved in PD, namely, (i) oxidative stress, (ii) mitochondrial dysfunction, (iii) inflammation, (iv) abnormal α-synuclein, and (v) endogenous neurotoxins, and proposed a hypothesis involving a damaging cycle. Oxidative stress-triggered aldehydes react with biogenic amines to produce endogenous neurotoxins. They cause mitochondrial dysfunction and the formation of inflammasomes, which induce the activation of neuroglial cells and the infiltration of T lymphocytes. The synergistic effect of these processes fosters chronic inflammation and α-synuclein aggregation and further exacerbates the impact of oxidative stress to establish a damaging cycle that eventually results in the degeneration of dopaminergic neurons. This damaging cycle provides an explanation of progressive neuronal death during the pathogenesis of PD and provides new potential targets beneficial for developing new drugs and approaches for clinical neuroprotection.

The 9-hole PEG test of upper extremity function: average values, test-retest reliability, and factors contributing to performance in people with Parkinson disease

BACKGROUND AND PURPOSE

Pegboard tests of hand dexterity are commonly used in clinical settings to assess upper extremity function in various populations. For individuals with Parkinson disease (PD), the clinical utility of pegboard tests has not been fully evaluated. Our purpose was to examine the commercially available 9-Hole Peg Test (9HPT) using a large sample of individuals with PD to determine average values, test-retest reliability, and factors predictive of 9HPT performance.

METHODS

A total of 262 participants with PD (67% men, Hoehn & Yahr stage = 2.3 ± 0.7) completed the 9HPT along with a battery of other tests including the Movement Disorder Society Unified PD Rating Scale-Motor Subscale III and Freezing of Gait Questionnaire.

RESULTS

Average time to complete the 9HPT was 31.4 ± 15.7 s with the dominant and 32.2 ± 12.4 s with the nondominant hand. Test-retest reliability of 2 trials performed with the same hand was high (dominant ICC2,1 = 0.88, nondominant ICC2,1 = 0.91). Women performed the test significantly faster than men, and nonfreezers significantly faster than freezers. For either hand, age, bradykinesia, and freezing of gait scores individually predicted significant portions of the variance in 9HPT time. Sex also was a significant predictor, but for the nondominant hand only. Tremor and rigidity did not predict performance.

DISCUSSION AND CONCLUSIONS

The 9HPT appears to be a clinically useful measure for assessing upper extremity function in individuals with PD. The 9HPT has advantages over previously used methods including standardization, known normative values for healthy controls, commercial availability, transportability, and ease of administration.

Entacapone promotes cAMP-dependent colonic Cl(-) secretion in rats

BACKGROUND

Entacapone is a promising drug used widely for the treatment of Parkinson's disease (PD) as a catechol-O-methyl transferase (COMT) inhibitor. However, entacapone has gastrointestinal side effects. The aim of this study was to investigate the effects of entacapone on the epithelial ion transport in rat distal colon, and explore the underlying mechanism.

METHODS

The study was performed on freshly isolated colonic mucosa-only, submucosa-only and mucosa-submucosa preparations in rat. The short circuit current (I(SC) ) was measured to determine electrogenic ion transport, and a scanning ion-selective electrode technique (SIET) was used to directly measure Cl(-) flux across the epithelium. The content of intracellular cAMP was measured with radioimmunoassay (RIA).

KEY RESULTS

Entacapone increased mucosal I(SC) in the rat distal colon. I(SC) was inhibited significantly by apical addition of diphenylamine-2,2'-dicarboxylic acid (DPC), a blocker of the Cl(-) channel, basolateral application of bumetanide, an inhibitor of Na(+) -K(+) -2Cl(-) co-transporter (NKCC), removal of Cl(-) from the bathing solution, and pretreatment with MDL 12330A, an inhibitor of adenylate cyclase. Inhibiting endogenous prostaglandin (PG) synthesis with indomethacin, and eliminating submucosal enteric neural activity with tetrodotoxin (TTX)-inhibited entacapone-evoked I(SC) increases. Similar results were also obtained when Cl(-) flux was measured with SIET. Entacapone significantly increased intracellular cAMP content, which was greatly inhibited by either indomethacin or TTX in the tissues containing submucosal plexus, and by only indomethacin in the mucosa-only preparations.

CONCLUSIONS & INFERENCES

Entacapone stimulates cAMP-dependent Cl(-) secretion in the rat colon, and this process is regulated by endogenous PG and the submucosal enteric nervous system.