Reduced Sympathetic Stimulus and Angiotensin 1–7 Are Related to Diastolic Dysfunction in Spinal Cord–Injured Subjects

Chronic spinal cord injury (SCI) is often associated with reductions in left ventricular (LV) diastolic function. Impairments in sympathetic activity and activation of the renin-angiotensin system are reported in SCI individuals and may hypothetically be implicated in this association. Hence, the present study verified the relationship between these two neuro-hormonal and cardiac functional and structural characteristics in SCI individuals. Twenty-two men with SCI (injury level above T6 and no voluntary motion below the injury) and 11 able-bodied men were evaluated by clinical, hemodynamic, laboratory, and echocardiographic analysis and had plasmatic renin, angiotensin I (ANGI), angiotensin II (ANGII), angiotensin 1-7 (ANG1-7), and noradrenaline levels measured. SCI subjects had lower noradrenaline (p = 0.003) and higher ANG1-7 (p = 0.009), but similar renin, ANGI, and ANGII levels when compared with able-bodied individuals. In SCI individuals, results of multi-variable analysis showed that higher Em, a marker of better LV diastolic function, was directly associated with ANG1-7 (p = 0.05) or ANG1-7/ANGII ratio (p = 0.007), whereas lower noradrenaline levels were independently associated with worse LV diastolic function, as assessed by E/Em ratio (p = 0.028). In conclusion, these results suggest that reduced sympathetic activity and expression of ANG1-7 may be involved in SCI-related diastolic dysfunction.