The effect of serum factors from patients with/without essential hypertensioin on membrane receptors from rat cerebral cortex vascular and cardiac muscle cells

TLDR: CSF levels of ACE are reduced in AD, correlating with Ab42 levels, and this results strengthen the hypothesis that ACE is associated with amyloidb pathology in AD.

Abstract: between CSF levels of RAS components and AD biomarkers. Methods: This study included 18 patients with probable AD recruited from the Behavioral and Cognitive Neurology Clinic of the Universidade Federal de Minas Gerais (UFMG), Brazil. A control group composed by 10 subjects undergoing lumbar puncture for anesthetic purpose was also enrolled. These subjects had no history of neurological and/or psychiatric disorders. After collection, CSF samples were centrifuged at 1,800 g for 10 minutes (40C) and stored at -800C until biomarker analysis. Ab40, Ab42, total tau (hTau), and phosphorylated-tau (pTau) were measured by enzyme-linked immunosorbent assay (ELISA) with commercially available kits (Innogenetics/Fujirebio, Gent, Belgium). Angiotensin (Ang) II, Ang-(1-7), ACE and ACE2 levels were also measured by ELISA according to the procedures supplied by the manufacturer (MyBioSource, San Diego, CA, USA). Results: All patients with AD met the CSF criteria for biomarker-based diagnosis, (i.e., IATI < 0.8; hTau/ Ab42 ratio > 0.52 and pTau/Ab42 ratio >0.08). Accordingly, we found decreased levels of Ab40 and Ab42, and increased levels of hTau and pTau in the CSF of patients with AD in comparison with controls (Table 1). Ang II and Ang-(1-7) were not detected in the CSF samples. Patients with AD presented decreased levels of ACE, but similar levels of ACE2 when compared with controls (Table 1; Fig.1A). Among patients with AD, ACE levels correlated positively with Ab42 levels (Fig.1B). Conclusions: CSF levels of ACE are reduced in AD, correlating with Ab42 levels. Our results strengthen the hypothesis that ACE is associated with amyloidb pathology in AD.