Roman Kopáčik

Small-nerve-fiber pathology in critical illness documented by serial skin biopsies

Introduction: Small‐fiber pathology can develop in the acute phase of critical illness and may explain chronic sensory impairment and pain in critical care survivors. Methods: Eleven adult ischemic stroke patients in a neurocritical care unit were enrolled in an observational cohort study. Intraepidermal nerve fiber density (IENFD) in the distal leg was assessed on admission to the intensive care unit and 10–14 days later, together with electrophysiological testing. Results: Of the 11 patients recruited, 9 (82%) had sepsis or multiple‐organ failure. Median IENFD on admission (5.05 fibers/mm) decreased significantly to 2.18 fibers/mm (P < 0.001), and abnormal IENFD was found in 6 patients (54.5%). Electrodiagnostic signs of large‐fiber neuropathy and/or myopathy were found in 6 patients (54.5%), and autonomic dysfunction was found in 2 patients (18.2%). Conclusion: Serial IENFD measurements confirmed the development of small‐fiber sensory involvement in the acute phase of critical illness. Muscle Nerve 52: 28–33, 2015

Alterations in the vascular architecture of the dorsal root ganglia in a rat neuropathic pain model.

An alteration in the structural arrangement of blood vessels identified by RECA immunohistochemistry was studied in a rat L4 dorsal root ganglia (L4-DRG) neuropathic pain model. We compared a three-dimensional (3-D) reconstruction of the vascular architecture surrounding bodies of the primary sensory neurons in the L4-DRG of naïve rats with that of rats that had surgically undergone unilateral sciatic nerve ligature. Rhodamine-conjugated dextran (Fluoro-Ruby) was used for retrograde labelling of neurons, the axons of which had been injured by nerve ligature. In contrast to DRG from naïve rats and contralateral DRG from operated rats, an increased proportion of RECA+ vascular area and the appearance of nest-like arrangements of blood vessels around neuronal bodies with injured axons were observed in L4-DRG ipsilateral to the sciatic nerve ligature. Fractal analysis confirmed a higher degree of vascular branching, irregularity, and tortuosity in L4-DRG related with sciatic nerve injury. The results suggest that nerve injury induces changes in vascular architecture in associated DRG.