Spinal cord injury is associated with enhanced peripheral chemoreflex sensitivity

Area of Science:

• Physiology
• Neurology
• Respiratory Medicine

Background:

• Sleep-disordered breathing (SDB) is common in chronic spinal cord injury (SCI) but its underlying mechanisms remain unclear.
• Peripheral chemoreceptors play a crucial role in regulating breathing and are potential contributors to SDB in SCI.

Purpose of the Study:

• To investigate whether peripheral chemoreceptor activity is enhanced in individuals with chronic SCI compared to able-bodied controls.
• To assess ventilatory responses to hyperoxia and carbon dioxide (CO2) challenges in SCI and able-bodied subjects.

Main Methods:

• Two protocols were employed: (1) assessing ventilatory response to hyperoxia, and (2) determining ventilatory response to a single breath of CO2 (SBCO2).
• Participants included individuals with cervical SCI (cSCI), thoracic SCI (tSCI), and able-bodied (AB) controls.
• Chemoreflex response was quantified as ∆VE/∆CO2 (L/min/mmHg) for SBCO2 and % change in tidal volume (VT) for hyperoxia.

Main Results:

• SCI subjects exhibited a significant decrease in VT and minute ventilation (VE) during hyperoxia compared to AB subjects.
• No significant differences in VT or VE during hyperoxia were observed between cSCI and tSCI groups.
• SCI participants demonstrated a significantly greater ventilatory response to SBCO2 compared to AB individuals.

Conclusions:

• Peripheral ventilatory chemoresponsiveness is elevated in individuals with chronic SCI.
• This enhanced peripheral chemoreceptor activity may be a key mechanism contributing to sleep-disordered breathing in the SCI population.