Degenerative Myelopathy in 18 Pembroke Welsh Corgi Dogs

Abstract

Abstract. Postmortem examination was performed on 18 Pembroke Welsh Corgi dogs (mean age 12.7 years) with clinical signs and antemortem diagnostic tests compatible with a diagnosis of degenerative myelopathy. Tissue sections from specific spinal cord and brain regions were systematically evaluated in all dogs. Axonal degeneration and loss were graded according to severity and subsequently compared across different spinal cord segments and funiculi. White matter lesions were identified in defined regions of the dorsal, lateral, and ventral funiculi. The dorsolateral portion of the lateral funiculus was the most severely affected region in all cord segments. Spinal cord segment T12 exhibited the most severe axonal loss. Spinal nerve roots, peripheral nerves, and brain sections were within normal limits, with the exception of areas of mild astrogliosis in gray matter of the caudal medulla. Dogs with more severe lesions showed significant progression of axonal degeneration and loss at T12 and at cord segments cranial and caudal to T12. Severity of axonal loss in individual dogs positively correlated with the duration of clinical signs. The distribution of axonal degeneration resembled that reported in German Shepherd Dog degenerative myelopathy but differed with respect to the transverse and longitudinal extent of the lesions within more clearly defined funicular areas. Although these lesion differences might reflect disease longevity, they could also indicate a form of degenerative myelopathy unique to the Pembroke Welsh Corgi dog.

Characterization of intercostal muscle pathology in canine degenerative myelopathy: A disease model for amyotrophic lateral sclerosis

“…Diagnosis of DM was confirmed by observation of profound axonal loss, myelin loss, and marked astrogliosis in the dorsal portion of the lateral white matter in the thoracic spinal cord and by the presence of cytoplasmic aggregates in spinal cord motor neurons that bind anti-SOD1 antibodies ( Fig. 1 ;Averill, 1973;March et al, 2009;Awano et al, 2009). See Supporting Information for a detailed description of the methods employed for histopathological assessments.…”

“…At disease onset, spinal reflexes are consistent with upper motor neuron (UMN) loss. Spinal cord pathology is most evident in the thoracic spinal cord early in the disease, spreads cranially and caudally, and becomes more severe as the disease progresses (Averill, 1973;March et al, 2009). More recently, clinical descriptions and histopathology indicate that DM reaches beyond the spinal cord also to involve motor units, at least in the advanced stages of disease (motor neuron, axon, and myofiber; Awano et al, 2009;Shelton et al, 2012).…”

Up-regulation of CB2 receptors in reactive astrocytes in canine degenerative myelopathy, a disease model of amyotrophic lateral sclerosis

“…DM diagnoses were confirmed histopathologically by assessing the mid to lower thoracic spinal cord segment for evidence of myelinated axon loss and pronounced astrogliosis in the dorsal portion of the lateral funiculus (Averill, 1973; March et al, 2009). Dogs that had exhibited clinical signs of DM but did not show the typical histopathology were presumed to have another cause for the myelopathy and were excluded from the study.…”

Characterization of thoracic motor and sensory neurons and spinal nerve roots in canine degenerative myelopathy, a potential disease model of amyotrophic lateral sclerosis

“…Briefly, disease stages at time of euthanasia were determined by using a clinical grading scale (Table III; Shelton et al, 2012). DM diagnoses were confirmed histopathologically by assessing the T6 cord segment for evidence of myelinated axon loss and pronounced astrogliosis in the dorsal portion of the lateral funiculus (Averill, 1973;March et al, 2009). Dogs that had exhibited clinical signs of DM but did not show the typical histopathology were presumed to have another cause for the myelopathy and were excluded from the study.…”