Basophilic inclusions and neuronal intermediate filament inclusions in amyotrophic lateral sclerosis and frontotemporal lobar degeneration

Frontotemporal dementia: Addressing the scattered harbingers of genetics and its relationship with glucose metabolism, bipolar disorder, and amyotrophic lateral sclerosis

Frontotemporal Dementia, also known by the name Pick's disease, is a rare form of dementia that can run for several generations. The two key characteristics are argyrophilic, spherical intraneuronal inclusions, which most frequently impact the frontal and temporal poles, and localized cortical atrophy (Pick bodies). Although personality decline and memory loss are frequently more severe than the visuospatial and apraxia disorders that are common in Alzheimer's disease, clinical overlap with other non-Alzheimer degenerative disorders is being increasingly recognized. The limbic system, which includes the hippocampus, entorhinal cortex, and amygdala, typically experiences the greatest levels of neuronal loss and degeneration. In the hippocampus's dentate fascia, several Pick bodies are frequently seen. Leukoencephalopathy and inflated cortical neurons are less specific symptoms (Pick cells). In this paper, we review the factors leading to Picks disease along with its pathophysiology, clinical manifestations, diagnosis, imaging, treatment, prognosis, and a comprehensive discussion on the same. We have also discussed the relationship of frontotemporal dementia with glucose metabolism, bipolar disorder, and amyotrophic lateral sclerosis, all of which are emerging fields of interest and need more studies.

An autopsy case report of neuronal intermediate filament inclusion disease presenting with predominantly upper motor neuron features

We describe an autopsy case of neuronal intermediate filament inclusion disease (NIFID), a subtype of frontotemporal lobar degeneration (FTLD) with the appearance of fused-in-sarcoma (FUS) inclusions (FTLD-FUS). A 57-year-old man developed dysarthria and dysphagia. One year and five months later, he was admitted to a hospital, and pseudobulbar palsy and right upper motor neuron signs were observed on examination. Needle electromyography revealed no active or chronic denervation. His neurological symptoms gradually deteriorated, and behavioral alterations occurred. He died of hemoperitoneum secondary to rupture of a ureteric tumor. The total duration of the disease was six years and 10 months. Neuropathologically, the frontal cortex, including the motor cortex, and the pyramidal tract were severely affected, whereas the lower motor neurons in the spinal cord and brainstem were mildly damaged. The striatum and substantia nigra were also severely damaged. Hyaline conglomerate inclusions, neuronal cytoplasmic inclusions with a distinct eosinophilic core (so-called cherry spot), Pick body-like inclusions, and eosinophilic round inclusions were observed in the remaining neurons. Immunohistochemical examination revealed that these inclusions were immunoreactive for FUS. HC inclusions were also immunoreactive for α-internexin and phosphorylated neurofilament protein. FUS-immunoreactive NCIs were abundant in the basal ganglia but not in the hippocampus, in contrast to previously reported NIFID cases. Furthermore, Bunina bodies identified by immunohistochemistry for cystatin C were also observed in the lower motor neurons. Bunina bodies may be present in NIFID. This case confirms the pathological heterogeneity of NIFID and supports the notion of the difference between amyotrophic lateral sclerosis and NIFID.

The unfolded protein response in amyotrophic later sclerosis: results of a phase 2 trial

Strong evidence suggests that endoplasmic reticulum (ER) stress plays a critical role in the pathogenesis of amyotrophic lateral sclerosis (ALS) through an altered regulation of proteostasis. Robust preclinical findings demonstrated that guanabenz selectively inhibits ER stress-induced eIF2α-phosphatase allowing misfolded protein clearance, reduces neuronal death and prolongs survival in in vitro and in vivo models. Its efficacy and safety in ALS patients are unknown. To address these issues, we conducted a multicentre, randomised, double-blind trial, with futility design. ALS patients with onset of symptoms within the previous 18 months were randomly assigned to receive in a 1:1:1:1 ratio guanabenz 64 mg, 32 mg, 16 mg or placebo daily for 6 months as add-on therapy to riluzole. The purpose of the placebo group blinding was safety but not efficacy. The primary outcome was the proportion of patients progressing to higher stages of disease in 6 months as measured by the ALS Milano-Torino staging compared to a historical cohort of 200 ALS patients. The secondary outcomes were the rate of decline in ALSFRS-R total score, slow vital capacity change, time to death, tracheotomy or permanent ventilation and serum light neurofilament level at 6 months. The primary analysis of efficacy was performed by intention-to-treat. Guanabenz 64 mg and 32 mg arms, both alone and combined, reached the primary hypothesis of non-futility with proportions of patients who progressed to higher stage of disease at 6 months significantly lower than that expected under the hypothesis of non-futility and significantly lower difference in the median rate of change of the ALSFRS-R total score. This effect was driven by patients with bulbar onset, none of whom (0/18) progressed to a higher stage of disease at 6 months compared with those in guanabenz 16 mg (4/8; 50%), historical cohort alone (21/49; 43%; p = 0.001) or plus placebo (25/60; 42%; p = 0.001). The proportion of patients who experienced at least one adverse event was higher in any guanabenz arm than in the placebo arm, with higher dosing arms having significantly higher proportion of drug-related side effects and the 64 mg arm significantly higher drop-out rate. The number of serious adverse events did not significantly differ between guanabenz arms and placebo. Our findings indicate that a larger trial with a molecule targeting the UPR pathway without the alpha-2 adrenergic related side-effect profile of guanabenz is warranted.

Differential regional infarction, neuronal loss and gliosis in the gerbil cerebral hemisphere following 30 min of unilateral common carotid artery occlusion

The degree of transient ischemic damage in the cerebral hemisphere is different according to duration of transient ischemia and cerebral regions. Mongolian gerbils show various lesions in the hemisphere after transient unilateral occlusion of the common carotid artery (UOCCA) because they have different types of patterns of anterior and posterior communicating arteries. We examined differential regional damage in the ipsilateral hemisphere of the gerbil after 30 min of UOCCA by using 2,3,5-triphenyltetrazolium chloride (TTC) staining, cresyl violet (CV) Nissl staining, Fluoro-Jade B (F-J B) fluorescence staining, and NeuN immunohistochemistry 5 days after UOCCA. In addition, regional differences in reactions of astrocytes and microglia were examined using GFAP and Iba-1 immunohistochemistry. After right UOCCA, neurological signs were assessed to define ischemic symptomatic animals. Moderate symptomatic gerbils showed several infarcts, while mild symptomatic gerbils showed selective neuronal death/loss in the primary motor and sensory cortex, striatum, thalamus, and hippocampus 5 days after UOCCA. In the areas, morphologically changed GFAP immunoreactive astrocytes and Iba-1 immunoreactive microglia were found, and their numbers were increased or decreased according to the damaged areas. In brief, our results demonstrate that 30 min of UOCCA in gerbils produced infarcts or selective neuronal death depending on ischemic severity in the ipsilateral cerebral cortex, striatum, thalamus and hippocampus, showing that astrocytes and microglia were differently reacted 5 days after UOCCA. Taken together, a gerbil model of 30 min of UOCCA can be used to study mechanisms of infarction and/or regional selective neuronal death/loss as well as neurological dysfunction following UOCCA.

Protein folding alterations in amyotrophic lateral sclerosis

Protein misfolding leads to the formation of aggregated proteins and protein inclusions, which are associated with synaptic loss and neuronal death in neurodegenerative diseases. Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that targets motor neurons in the brain, brainstem and spinal cord. Several proteins misfold and are associated either genetically or pathologically in ALS, including superoxide dismutase 1 (SOD1), Tar DNA binding protein-43 (TDP-43), Ubiquilin-2, p62, VCP, and dipeptide repeat proteins produced by unconventional repeat associated non-ATG translation of the repeat expansion in C9ORF72. Chaperone proteins, including heat shock proteins (Hsp׳s) and the protein disulphide isomerase (PDI) family, assist in protein folding and therefore can prevent protein misfolding, and have been implicated as being protective in ALS. In this review we provide an overview of the current literature regarding the molecular mechanisms of protein misfolding and aggregation in ALS, and the role of chaperones as potential targets for therapeutic intervention. This article is part of a Special Issue entitled SI:ER stress.