Chitotriosidase, a biomarker of amyotrophic lateral sclerosis, accentuates neurodegeneration in spinal motor neurons through neuroinflammation.

BACKGROUND: Cerebrospinal fluid from amyotrophic lateral sclerosis patients (ALS-CSF) induces neurodegenerative changes in motor neurons and gliosis in sporadic ALS models. Search for identification of toxic factor(s) in CSF revealed an enhancement in the level and enzyme activity of chitotriosidase (CHIT-1). Here, we have investigated its upregulation in a large cohort of samples and more importantly its role in ALS pathogenesis in a rat model. METHODS: CHIT-1 level in CSF samples from ALS (n = 158), non-ALS (n = 12) and normal (n = 48) subjects were measured using ELISA. Enzyme activity was also assessed (ALS, n = 56; non-ALS, n = 10 and normal-CSF, n = 45). Recombinant CHIT-1 was intrathecally injected into Wistar rat neonates. Lumbar spinal cord sections were stained for Iba1, glial fibrillary acidic protein and choline acetyl transferase to identify microglia, astrocytes and motor neurons respectively after 48 h of injection. Levels of tumour necrosis factor-α and interleukin-6 were measured by ELISA. FINDINGS: CHIT-1 level in ALS-CSF samples was increased by 20-fold and it can distinguish ALS patients with a sensitivity of 87% and specificity of 83.3% at a cut off level of 1405.43 pg/ml. Enzyme activity of CHIT-1 was also 15-fold higher in ALS-CSF and has a sensitivity of 80.4% and specificity of 80% at cut off value of 0.1077989 µmol/µl/min. Combining CHIT-1 level and activity together gave a positive predictive value of 97.78% and negative predictive value of 100%. Administration of CHIT-1 increased microglial numbers and astrogliosis in the ventral horn with a concomitant increase in the levels of pro-inflammatory cytokines. Amoeboid-shaped microglial and astroglial cells were also present around the central canal. CHIT-1 administration also resulted in the reduction of motor neurons. CONCLUSIONS: CHIT-1, an early diagnostic biomarker of sporadic ALS, activates glia priming them to attain a toxic phenotype resulting in neuroinflammation leading to motor neuronal death.

Family Caregivers' Experiences with Dying and Bereavement of Individuals with Motor Neuron Disease in India.

Motor neuron disease (MND) is a progressive neurodegenerative disease. Ideal management plan in MND includes palliative care initiated from the time of diagnosis. At present, most of the neurodegenerative conditions are cared for at home. Neuropalliative care is an emerging concept in India and social workers are integral team members in this process. The primary aims of the study were to explore (a) the caregivers' experiences of the end-of-life stage, and (b) the sources of support for individuals and their caregivers with MND at the end-of-life stage. In-depth interviews were conducted with seven bereaved caregivers of individuals with MND from a national tertiary referral care center for neuropsychiatry in South India. Interviews were conducted either in person or by telephone. Thematic analysis was done using the constant comparative method. Major themes derived from the interviews were: (1) Transition from person to patient, (2) support, (3) death, and (4) impact on the caregivers. Mapping of themes identified "Support received during advanced stages" as the central theme influencing all other themes. The need for a care manager seems evident and is a role that can be effectively fulfilled by the care teams' social workers.