ABSTRACT
Background: Long-COVID is a complicated condition with prolonged SARS-CoV-2 symptoms. Several variables have been studied in this illness. Among the less studied variables are galanin and its receptor (GalR1). The Galanin system is involved in the pathophysiology of several age-related chronic disorders, including alcoholism, chronic pain, and bowel and skin inflammation. The aim of the study is to correlate the galanin system parameters with clinical and biochemical variables in Long-COVID. Methods: Serum levels of albumin, electrolytes, GAL, GALR1, and C-reactive protein (CRP) are measured by ELISA technique in 90 Long-COVID patients and 60 recovered subjects who are free from any symptoms of Long-COVID. Results: The study showed a significantly increased Galanin, GALR1, and the Gal/GALR1 ratio. On the contrary, serum albumin, total calcium, ionized calcium, total magnesium, and the ionized calcium/magnesium ratio were significantly decreased. Galanin and Galanin/GALR1 showed significant age-related associations ({rho}=0.353, p<0.01) and ({rho}=0.218, p<0.05), respectively. The lowest SpO2 was associated with Galanin ({rho}=-0.295, p<0.01) and GALR1 ({rho}=-0.232, p<0.05), respectively. According to ROC analysis results, the highest sensitivities for differentiating between patients and non-patient subjects were Galanin (71.7%) and GALR1 (60.0%). Conclusions: Galanin, GALR1, and Long-COVID disease are directly correlated. However, more research is needed to find out exactly what roles plasma Galanin and its receptor play in Long-COVID disease.