Repetitive transcranial magnetic stimulation (rTMS) as a new non-invasive painless procedure has been tested for augmentation of motor performance and reduction of spasticity in post-stroke patients. Stroke patients (N = 34) were recruited for rTMS treatment and brain activity analysis (EEG) was performed before and after rTMS. The effect of rTMS was evaluated using National Institute of Health Stroke Scale (NIHSS), Barthel -Index and Ashworth Scale. The content of L-tryptophan (L-TRP), L-kynurenine (L-KYN), kynurenic acid (KYNA) and anthranilic acid (ANA) was determined in the serum of stroke patients before the 1st, after the 5th and after 10th rTMS application using high performance liquid chromatography. In a separate experiment, L-TRP metabolites were determined in the serum of an independent group of stroke patients (N=47) and control subjects (N = 6). The content of L-TRP and L-TRP metabolites in the serum of stroke patients was significantly increased, L-TRY was 121% of CO; L-KYN 161% of CO, p<0.015; ANA 280 % of CO, p<0.001; KYNA 243% of CO, p<0.001, compared to control subjects. Similar changes were found in stroke patients recruited for rTMS. After the 10th rTMS treatment L-KYN and ANA levels increased moderately but significantly in the serum and it was L-KYN 107%, p<0.01; ANA 110%, p = 0.055, versus the value before 1st rTMS, respectively. The ratios L-KYN/TRP and ANA/KYNA increased moderately but significantly after the 10th rTMS. Creatin kinase and prolactin levels were in normal range during rTMS. Stroke patients treated with rTMS have shown a significant enhancement of motor performance and moderate reduction of spasticity. The alteration of ANA/KYNA ratio after rTMS might be of significance with respect to the clinical improvement of patients. The present study gives favour for rTMS as a means for neurorehabilitation of patients after stroke. Notable, the management of therapies following rTMS are of importance for an improvement of hand and fingers activities, as observed within this study.

BackgroundStochastic resonance therapy (SRT) is used for rehabilitation of patients with various neuropsychiatric diseases. An alteration in tryptophan metabolism along the kynurenine pathway has been identified in the central and peripheral nervous systems in patients with neuroinflammatory and neurodegenerative diseases and during the aging process. This study investigated the effect of SRT as an exercise activity on serum tryptophan metabolites in healthy subjects.MethodsSerum L-tryptophan, L-kynurenine, kynurenic acid, and anthranilic acid levels were measured one minute before SRT and at one, 5, 15, 30, and 60 minutes after SRT. We found that SRT affected tryptophan metabolism. Serum levels of L-tryptophan, L-kynurenine, and kynurenic acid were significantly reduced for up to 60 minutes after SRT. Anthranilic acid levels were characterized by a moderate, non significant transient decrease for up to 15 minutes, followed by normalization at 60 minutes. Tryptophan metabolite ratios were moderately altered, suggesting activation of metabolism after SRT. Lowering of tryptophan would generally involve activation of tryptophan catabolism and neurotransmitter, protein, and bone biosynthesis. Lowering of kynurenic acid by SRT might be relevant for improving symptoms in patients with neuropsychiatric disorders, such as Parkinson’s disease, Alzheimer’s disease, schizophrenia, and depression, as well as certain pain conditions.

A female 49 years old patient with vestibular schwannoma developed normal pressure hydrocephalus. Patient complained about gait disturbance, urinary incontinence and memory impairment. Investigation of clinical parameter and measurement of kynurenic acid in the cerebrospinal fluid (CSF) and serum in patients with normal pressure hydrocephalus and in corresponding controls (CO; N=15) were performed. Within investigated parameters significant increase of protein and IgG levels in CSF were found in patient with normal pressure hydrocephalus. Furthermore, kynurenic acid was increased in the CSF by 60% and in the serum by 40%, comparing to CO subjects. Kynurenic acid level in CO was in the CSF and serum 2.77 ± 0.23 and 53.4 ± 4.0 nM, respectively. Three lumbar punctures were applied to patient with normal pressure hydrocephalus and clinical parameters partially normalized and lowering of kynurenic acid levels in CSF and serum were observed. Patient was improving after each lumbar puncture but the effect was transient, therefore permanent CSF shunting was recommended. After that a complete remission of symptoms occurred. Revealed data indicate a significant advantage of single punctures in management of treatment for normal pressure hydrocephalus. Increase of kynurenic acid in CSF represents interesting parameter. It is questionable if occurrence of cognition impairment and/or dementia in patients with normal pressure hydrocephalus might be related to an enhancement of kynurenic acid in the CNS.

No abstract