Soluble urokinase-type plasminogen activator receptor (suPAR) is elevated in caregivers of patients with parkinsonism

Caregivers are integral to the care of those with neurological disorders such as Parkinson's Disease (PD), but are often burdened by stress, anxiety, and depression. Previous research has suggested that the foundation of such stress is low-grade systemic inflammation, as evidenced by increased interleukin 6 (IL-6) and C-reactive protein (CRP) levels. Soluble urokinase-type plasminogen activator receptor (suPAR) is a kidney disease risk factor and marker of chronic inflammation that integrates psycho-social stress and organ dysfunction. Caregivers of PD experience an extraordinary amount of stress and suPAR's role as prognostic marker has not yet been assessed in caregivers of PD. The aim of this study was to determine the relationship between suPAR levels and PD caregiver burden. Healthy volunteers who accompanied patients with parkinsonism (n = 35) donated blood samples, and complete blood counts (CBC), CRP, and suPAR levels were measured. Participants were then interviewed by telephone and stratified into primary and non-primary caregiver groups. Their caregiver burden was quantified through the Zarit Caregiver Burden Short Form (ZBI-12). The resultant data demonstrated higher plasma levels of suPAR and ZBI-12 scores for the primary caregiver group relative to the non-primary caregiver group (suPAR level: 3.73 vs. 2.72 ng/mL, p = 0.01; ZBI-12: 18.57 vs. 5.4, p < 0.0001; Table). The data also revealed a moderate positive correlation between suPAR and ZBI-12 scores. These findings not only demonstrate a correlation between elevated suPAR and caregiving burden in PD, but also further support and raise awareness for the overall psychosocial burden and stress experienced by those caregivers.