To date there is no diagnostic biomarker for mild stroke, although elevation of inflammatory biomarkers has been reported at early stages. Previous studies implicated acetylcholinesterase (AChE) involvement in stroke, and circulating AChE activity reflects inflammatory response, since acetylcholine suppresses inflammation. Therefore, carriers of polymorphisms that modify cholinergic activity should be particularly susceptible to inflammatory damage. Our study sought diagnostic values of AChE and Cholinergic Status (CS, the total capacity for acetylcholine hydrolysis) in suspected stroke patients. For this purpose, serum cholinesterase activities, butyrylcholinesterase-K genotype and inflammatory biomarkers were determined in 264 ischemic stroke patients and matched controls during the acute phase. AChE activities were lower (P<0.001), and butyrylcholinesterase activities were higher in patients than in controls (P=0.004). When normalized to sampling time from stroke occurrence, both cholinergic parameters were correlated with multiple inflammatory biomarkers, including fibrinogen, interleukin-6 and C-reactive protein (r=0.713, r=0.607; r=0.421, r=0.341; r=0.276, r=0.255; respectively; all P values<0.001). Furthermore, very low AChE activities predicted subsequent nonsurvival (P=0.036). Also, carriers of the unstable butyrylcholinesterase-K variant were more abundant among patients than controls, and showed reduced activity (P<0.001). Importantly, a cholinergic score combining the two cholinesterase activities discriminated between 94.3% matched pairs of patients and controls, compared with only 75% for inflammatory measures. Our findings present the power of circulation cholinesterase measurements as useful early diagnostic tools for the occurrence of stroke. Importantly, these were considerably more distinctive than the inflammatory biomarkers, albeit closely associated with them, which may open new venues for stroke diagnosis and treatment.

Background and Purpose—: Inflammation may contribute to cognitive impairment after stroke. Inflammatory markers are associated with hippocampal atrophy. We tested whether markers of inflammation, erythrocyte sedimentation rate (ESR), and serum levels of C-reactive protein are associated with reduced hippocampal volume and poor cognitive performance among stroke survivors. Methods—: We analyzed 368 consecutive cases from our prospective study of first-ever mild–moderate stroke patients. MRI, cognitive tests, and inflammatory markers were determined. Patients were reevaluated 6 and 12 months after the event. Results—: ESR remained unchanged in follow-up examinations, suggesting a chronic inflammation background in some patients. Higher levels of C-reactive protein and ESR were associated with worse performance in cognitive tests, particularly memory scores. This association was maintained for ESR (but not C-reactive protein) after adjustment for confounders ( P =0.002). Patients with smaller hippocampi had inferior cognitive results. Moreover, in a multivariate regression model, higher ESR values (but not C-reactive protein) were related to reduced hippocampal volume ( P =0.049). Conclusions—: This report shows a strong relationship between ESR and hippocampal volume, as well as with cognitive performance among poststroke patients. This could plausibly relate to incipient cognitive decline via hippocampal pathways.

MicroRNAs (miRNAs) can repress multiple targets, but how a single de-balanced interaction affects others remained unclear. We found that changing a single miRNA–target interaction can simultaneously affect multiple other miRNA–target interactions and modify physiological phenotype. We show that miR-608 targets acetylcholinesterase (AChE) and demonstrate weakened miR-608 interaction with the rs17228616 AChE allele having a single-nucleotide polymorphism (SNP) in the 3′-untranslated region (3′UTR). In cultured cells, this weakened interaction potentiated miR-608-mediated suppression of other targets, including CDC42 and interleukin-6 (IL6). Postmortem human cortices homozygote for the minor rs17228616 allele showed AChE elevation and CDC42/IL6 decreases compared with major allele homozygotes. Additionally, minor allele heterozygote and homozygote subjects showed reduced cortisol and elevated blood pressure, predicting risk of anxiety and hypertension. Parallel suppression of the conserved brain CDC42 activity by intracerebroventricular ML141 injection caused acute anxiety in mice. We demonstrate that SNPs in miRNA-binding regions could cause expanded downstream effects changing important biological pathways.

Significance: Ischemic stroke triggers peripheral immunosuppression, increasing the susceptibility to poststroke pneumonia that is linked with poor survival. The poststroke brain initiates intensive communication with the immune system, and acetylcholine contributes to these messages; but the responsible molecules are yet unknown. We discovered a “changing of the guards,” where microRNA levels decreased but small transfer RNA fragments increased in poststroke blood. This molecular switch may rebalance acetylcholine signaling in CD14 ⁺ monocytes by regulating their gene expression and modulating poststroke immunity. Our observations point to transfer RNA fragments as molecular regulators of poststroke immune responses that may be potential therapeutic targets.

The K variant of butyrylcholinesterase (BChE-K, 20% incidence) is a long debated risk factor for Alzheimer disease (AD). The A539T substitution in BChE-K is located at the C terminus, which is essential both for BChE tetramerization and for its capacity to attenuate β-amyloid (Aβ) fibril formation. Here, we report that BChE-K is inherently unstable as compared with the “usual” BChE (BChE-U), resulting in reduced hydrolytic activity and predicting prolonged acetylcholine maintenance and protection from AD. A synthetic peptide derived from the C terminus of BChE-K (BSP-K), which displayed impaired intermolecular interactions, was less potent in suppressing Aβ oligomerization than its BSP-U counterpart. Correspondingly, highly purified recombinant human rBChE-U monomers suppressed β-amyloid fibril formation less effectively than dimers, which also protected cultured neuroblastoma cells from Aβ neurotoxicity. Dual activity structurally derived changes due to the A539T substitution can thus account for both neuroprotective characteristics caused by sustained acetylcholine levels and elevated AD risk due to inefficient interference with amyloidogenic processes.

MicroRNA-132 (miR-132) targets acetylcholinesterase (AChE) and potentiates the cholinergic blockade of inflammatory reactions in cultured cells and experimental mice, but the implications of this interaction to human inflammatory disease remained unexplored. This study aimed to test whether miR-132 is causally involved in anti-inflammatory reactions of patients with inflammatory bowel disease (IBD) and modulates vagal tone and consequently inflammation in patients with IBD. We prospectively measured inflammation readouts and the cholinergic status (total capacity for hydrolyzing acetylcholine in one's circulation), and AChE activity in 2 independent cohorts of patients with IBD and quantified miR-132 levels in intestinal tissue biopsies removed at colonoscopy from inflamed and apparently quiescent tissues of tested volunteers. MiR-132 levels are higher in inflamed compared with apparently quiescent intestinal biopsies from patients with IBD. Correspondingly, the cholinergic status and AChE activity was significantly lower in patients with IBD suffering from moderate-severe disease as compared with healthy controls or patient with IBD presenting low disease severity. Patients with IBD (n = 16) presented lower AChE activity compared with healthy controls (n = 33; 289 ± 128 AU versus 391 ± 102 AU, P = 0.001), and a negative correlation between AChE activity and C-reactive protein levels (r = -0.47, P = 0.01). Corroborating these observations in an additional cohort of participants, C-reactive protein and AChE activity were negatively correlated in patients with moderate-severe disease (n = 16; r = -0.6, P = 0.04) and positively correlated in healthy controls (n = 74, r = 0.24, P = 0.046). Taken together, these findings support an inflammation-dependent homeostatic role for the regulation by miR-132 of AChE in IBD, opening new venues for therapeutic interference.