Unusual expression of peripheral blood Alzheimer's markers, inflammatory cytokines, and cholinergic biomarkers in chronic kidney disease patients with cognitive dysfunction: Therapeutic impact of recombinant human erythropoietin (rHuEPO).

BACKGROUND

Patients with chronic kidney disease (CKD) are at a significantly increased risk of developing Alzheimer's disease (AD) and cognitive dysfunction compared to the general population. While recombinant human erythropoietin (rHuEPO) is commonly used to treat anemia in CKD, emerging evidence indicates that it also possesses neuroprotective properties. This study aimed to evaluate the therapeutic impact of rHuEPO on platelet expression of amyloid precursor protein (APP) proteolytic fragments, apolipoprotein E (ApoE), glycogen synthase kinase 3β (GSK3β), total Tau, and phosphorylated Tau species (P-Tau181, P-Tau217, and P-Tau231), along with plasma levels of APP cleaving enzymes, P-Tau217, P-Tau231, inflammatory cytokines, and cholinergic markers in CKD patients with cognitive dysfunction.

METHODS

A total of 60 CKD patients were enrolled, including 30 without cognitive dysfunction and 30 with cognitive dysfunction, as determined by neuropsychological assessment. Platelet protein expression levels of total Tau, P-Tau181, P-Tau217, P-Tau231, and ApoE were analyzed using Western blotting. Gene expression levels of APP-cleaving enzymes, ApoE, GSK3β, and MAPT in platelets were assessed by RT-PCR. Plasma concentrations of APP-cleaving enzymes, inflammatory cytokines, cholinergic markers, P Tau217, and P-Tau231 were quantified. Results were compared with healthy controls, normocytic normochromic anemia, and AD.

RESULTS

CKD patients with cognitive dysfunction showed significant alterations in the expression of platelet proteins (total Tau, P-Tau181, P Tau217, P-Tau231, and ApoE) and related genes (APP cleaving enzymes, ApoE, GSK3β, and MAPT), resembling the molecular profile observed in AD. Additionally, plasma levels of APP cleaving enzymes, inflammatory cytokines, cholinergic markers, and phosphorylated Tau species (P-Tau217 and P-Tau231) were significantly altered in these patients. Notably, after 6 months of rHuEPO therapy, these biomarkers showed marked improvement in CKD patients with cognitive dysfunction.

CONCLUSION

These findings suggest that rHuEPO may offer therapeutic benefits beyond anemia correction, potentially serving as a supportive treatment for cognitive dysfunction in CKD by modulating AD-related peripheral biomarkers.