Chitotriosidase (CHIT1) is increased in microglia and macrophages in spinal cord of amyotrophic lateral sclerosis and cerebrospinal fluid levels correlate with disease severity and progression.

OBJECTIVES: Neurochemical markers of amyotrophic lateral sclerosis (ALS) that reflect underlying disease mechanisms might help in diagnosis, staging and prediction of outcome. We aimed at determining the origin and differential diagnostic and prognostic potential of the putative marker of microglial activation chitotriosidase (CHIT1). METHODS: Altogether 316 patients were included, comprising patients with sporadic ALS, ALS mimics (disease controls (DCo)), frontotemporal lobar degeneration (FTLD), Creutzfeldt-Jakob disease (CJD), Alzheimer's disease (AD), Parkinson's disease (PD) and healthy controls (Con). CHIT1 and neurofilament levels were determined in cerebrospinal fluid (CSF) and blood and analysed with regard to diagnostic sensitivity and specificity and prognostic performance. Additionally, postmortem tissue was analysed for CHIT1 expression. RESULTS: In ALS, CHIT1 CSF levels were higher compared with Con (p<0.0001), DCo (p<0.05) and neurodegenerative diseases (AD p<0.05, PD p<0.01, FTLD p<0.0001) except CJD. CHIT1 concentrations were correlated with ALS disease progression and severity but not with the survival time, as did neurofilaments. Serum CHIT1 levels were not different in ALS compared with any other study group. In the spinal cord of patients with ALS, but not Con, AD or CJD cases, CHIT1 was expressed in the corticospinal tract and CHIT1 staining colocalised with markers of microglia (IBA1) and macrophages (CD68). CONCLUSIONS: CHIT1 concentrations in the CSF of patients with ALS may reflect the extent of microglia/macrophage activation in the white matter of the spinal cord. CHIT1 could be a potentially useful marker for differential diagnosis and prediction of disease progression in ALS and, therefore, seems suitable as a supplemental marker for patient stratification in therapeutic trials.

The combination of dopa-responsive parkinsonian syndrome and motor neuron disease.

BACKGROUND: Idiopathic Parkinson's syndrome (IPS) and motor neuron disorders (MND) are generally considered as distinct clinicopathological entities. However, cooccurrence of different neurodegenerative disorders is more frequent than would be expected. Therefore, there is an ongoing discussion whether some entities represent parts of a common spectrum. OBJECTIVE AND METHODS: We describe clinical hallmarks and treatment options in a group of 8 patients who had combined features of both a dopa-responsive parkinsonian syndrome and MND. RESULTS: All patients exhibited a typical clinical picture of IPS, and all were treated with levodopa or other dopaminergic drugs with good clinical response. The patients also showed clinical and electrophysiological signs of upper and/or lower motor neuron degeneration. Noticeably, in contrast to well-known distinct entities like the amyotrophic lateral sclerosis-parkinsonism/ dementia complex in southwest New Guinea, we did not observe any cognitive decline during the observation period except in 1 patient. CONCLUSION: This comorbidity of two neurodegenerative diseases supports the ongoing discussion of a pathophysiological and clinical overlap of disease processes. Due to the potent pharmacological options for the IPS symptoms in these overlap syndromes, these patients should be offered optimal symptomatic dopaminergic therapy.