Procarboxypeptidase U (proCPU, TAFI, proCPB2) in cerebrospinal fluid during ischemic stroke is associated with stroke progression, outcome and blood–brain barrier dysfunction

Abstract

Background Procarboxypeptidase U (proCPU, TAFI, proCPB2), the zymogen of CPU, which is a potent antifibrinolytic enzyme and a modulator of inflammation, has previously been investigated in plasma of stroke patients, but so far, no information on the proCPU levels in cerebrospinal fluid (CSF) during acute ischemic stroke (AIS) is available. Objectives This case-control observational study investigates proCPU in CSF of AIS patients compared with controls with an intact blood-brain barrier (BBB) and evaluates the relationship of CSF/plasma proCPU ratios with stroke parameters. Methods A sensitive HPLC-based enzymatic assay was used to determine proCPU levels in CSF of non-thrombolyzed patients in the hyperacute phase (< 24 h after onset) of AIS (n = 72). Individuals (n = 32) without stroke, an intact BBB and no apparent abnormalities in biochemical and microbiological tests, served as controls. Relations between the CSF/plasma proCPU ratio and (i) stroke severity, (ii) stroke progression/recurrence, (iii) stroke outcome and (iv) BBB dysfunction (CSF/serum albumin ratio) were assessed. Results Mean (SEM) proCPU levels were elevated in the CSF of stroke patients compared with controls (4.36 (0.23) U L vs. 3.50 (0.23) U L ). Higher median [IQR] CSF/plasma proCPU ratios were found in patients with stroke progression ((6.0 [4.2-6.9]) × 10 ) and poor outcome ((6.4 [3.9-7.0]) × 10 ) after 3 months (modified Rankin Scale; mRS > 3) compared with patients without progression ((3.9 [2.7-5.4]) × 10 ) or better outcome ((4.0 [2.8-5.0]) × 10 ). In stroke patients with a disrupted BBB, proCPU ratios were higher compared with stroke patients with an intact BBB ((6.4 [5.8-9.0]) × 10 vs. (3.7 [2.8-5.0]) × 10 ). Conclusions ProCPU is increased in CSF during hyperacute ischemic stroke and is associated with stroke progression and outcome after 3 months, most likely due to BBB dysfunction in the hyperacute phase of ischemic stroke.

Small Vessel Disease-Related Dementia: An Invalid Neurovascular Coupling?

“…A loss of cholinergic neurons in 40% of demented vascular patients was reported, accompanied by reduced ACh activity in the cortex, hippocampus, and striatum [152]. Post-mortem SVD studies revealed lower choline acetyltransferase (ChAT) activity when compared with the controls [153], and SVD patients have lower CSF concentrations of Ach [151,[154][155][156]. In fact, in the experimental condition, the selective muscarinic antagonism by atropine, for example, has dramatic consequences in the CA1 region, [157].…”

Carboxypeptidase U (CPU, TAFIa, CPB2) in Thromboembolic Disease: What Do We Know Three Decades after Its Discovery?

“…In non-thrombolysed patients, significant plasma proCPU activation (reflecting fibrinolytic activity and/or activation of the coagulation cascade) in the first 72 h after ischemic stroke onset was observed [35]. In the same study cohort, increased proCPU levels were measured in the cerebrospinal fluid of stroke patients [36]. More pronounced plasma proCPU consumption and increased proCPU levels in cerebrospinal fluid have been associated with blood-barrier dysfunction, stroke progression and poor outcome [35,36].…”

“…In the same study cohort, increased proCPU levels were measured in the cerebrospinal fluid of stroke patients [36]. More pronounced plasma proCPU consumption and increased proCPU levels in cerebrospinal fluid have been associated with blood-barrier dysfunction, stroke progression and poor outcome [35,36]. Alessi et al demonstrated that stroke patients at admission had higher CPU + CPUi levels compared to control subjects and that CPU + CPUi levels were associated with stroke severity in non-thrombolysed patients [37].…”

“…Determination of these cleavage products provides insight into the in vivo activation of the proCPU pathway and thus past and ongoing CPU formation. Although it is not possible to determine the fraction of CPU at a specific time point by these methods, consecutive samplings allow to relatively assess the amount of CPU that has been generated between two specific time points and can possibly provide complementary information to activity-based assays in patient populations where fibrinolysis is impaired [36,58,61,62,79]. Antibody pairs for application in sandwich-ELISAs have been developed and validated by Ceresa and coworkers [12].…”

Current Approaches and Future Perspectives for Nanobodies in Stroke Diagnostic and Therapy

“…It acts as a negative feedback regulator, i.e., inhibits fibrinolysis. In stroke patients TAFI is elevated in the acute phase of ischemia [92] and is associated with a poor outcome [93]. Furthermore, studies on murine stroke models have shown that anti-TAFI monoclonal antibodies (MA-TCK26D6) reduce fibrinogen deposition, hence improving reperfusion [94].…”