Plasma tissue kallikrein level is negatively associated with incident and recurrent stroke: a multicenter case-control study in China

Tissue Kallikrein supplementation in ischemic phase protects the neurovascular unit and attenuates reperfusion-induced injury in ischemic stroke

Tissue kallikrein (TK) has emerged as a potential neuroprotective agent in ischemic stroke (IS), yet the optimal timing and mechanisms of TK therapy remain unclear. Here, we established a causal link between lower baseline TK levels and an increased risk of stroke through a retrospective, multicenter cohort study involving 2115 initially non-stroke subjects monitored for 5 years. Sequentially, we observed a notable increase in bradykinin receptor 2 (B2R) levels during the ischemic phase of the IS model, while levels of TK and bradykinin receptor 1 (B1R) remained stable. Intriguingly, both B1R and B2R exhibited a significant elevation 24 h after reperfusion. Further investigations in preclinical models demonstrated that TK supplementation activates the PI3K/AKT signaling pathway via enhanced B2R expression during the ischemic phase, leading to nuclear translocation of Hif-1α. This activation enhances the expression of VEGF and eNOS, thereby fortifying the neurovascular unit. Moreover, it suppresses the activation of the kallikrein-kinin system induced by reperfusion injury, effectively reducing inflammation, ROS production, apoptosis, and endothelial barrier dysfunction. Thus, our findings highlight the significance of TK supplementation during the ischemic phase in attenuating reperfusion-induced injury in IS, providing a mechanistic rationale for determining the optimal timing for TK supplementation therapy.

Ulinastatin attenuated cardiac ischaemia/reperfusion injury by suppressing activation of the tissue kallikrein-kinin system

BACKGROUND AND PURPOSE

Ulinastatin has beneficial effects in patients undergoing coronary artery bypass grafting (CABG) surgery due to its anti-inflammatory properties, but the underlying mechanism remains unclear.

EXPERIMENTAL APPROACH

We used samples from patients undergoing CABG, a model of cardiac ischaemia-reperfusion injury (IRI) in mice and murine cardiac endothelial cell cultures to investigate links between ulinastatin, the kallikrein-kinin system (KKS), endothelial dysfunction and cardiac inflammation in the response to ischaemia/reperfusion injury (IRI). These links were assessed using clinical investigations, in vitro and in vivo experiments and RNA sequencing analysis.

KEY RESULTS

Ulinastatin inhibited the activity of tissue kallikrein, a key enzyme of the KKS, at 24 h after CABG surgery, which was verified in our murine cardiac ischaemia-reperfusion model. Under normal conditions, ulinastatin only inhibited kallikrein activity but did not affect bradykinin (B1/B2) receptors. Ulinastatin protected against IRI, in vivo and in vitro, by suppressing activation of the kallikrein-kinin system and down-regulating B1/B2 receptor-related signalling pathways including ERK/ iNOS, which resulted in enhanced endothelial barrier function, mitigation of inflammation and oedema, decreased infarct size, improved cardiac function and decreased mortality. Inhibition of kallikrein and knockdown of B1, but not B2 receptors prevented ERK translocation into the nucleus, reducing reperfusion-induced injury in murine cardiac endothelial cells.

CONCLUSIONS AND IMPLICATIONS

Treatment with ulinastatin exerts a protective influence on cardiac reperfusion by suppressing activation of the kallikrein-kinin system. Our findings highlight the potential of targeting kallikrein /bradykinin receptors to alleviate endothelial dysfunction, thus improving cardiac IRI.

IL-6 and stroke recurrence in ischemic stroke

Objective: This study aimed to evaluate the predictive value of IL-6 for stroke recurrence in acute ischemic stroke.Methods: Patients who were admitted within 48 h of onset were included. At 3-month, stroke recurrence was assessed. IL-6 levels were measured in serum samples taken upon admission.Results: Out of the 305 patients, 47 (15.4%) experienced a stroke recurrence. The risk of stroke recurrence increased by 8% (OR: 1.08; 95% CI: 1.04-1.11; p < 0.001) for every 1 pg/ml increase in IL-6 serum level, both in unadjusted and adjusted analyses (6%; OR: 1.06; 95% CI: 1.02-1.10; p = 0.001).Conclusion: The study supports the usefulness of IL-6 as a predictive biomarker for stroke recurrence after acute ischemic stroke.

The effectiveness and safety of human urinary kallidinogenase in acute ischemic stroke patients undergoing endovascular therapy

The effectiveness and safety of human urinary kallidinogenase (HUK) in acute ischemic stroke (AIS) patients undergoing endovascular therapy (EVT) due to large vessel occlusion (LVO) was unclear. A pooled analysis was performed using individual data from the DEVT and RESCUE BT trials. Patients were divided into two groups based on HUK treatment. The primary outcome was the 90-day modified Rankin Scale (mRS) score. Safety outcomes included 90-day mortality and symptomatic intracranial hemorrhage (sICH) within 48 hours. A total of 1174 patients were included in the study. Of these, 150 (12.8%) patients received HUK. The adjusted common odds ratio (OR) of the mRS score was 1.458 (95% confidence interval [CI] = 1.072-1.983; p = 0.016) favoring HUK. The incidence of sICH (2.0% vs. 8.6%; adjusted OR: 0.198; 95% CI: 0.061-0.638; p = 0.007) and mortality (11.3% vs.18.5%; adjusted OR: 0.496; 95% CI: 0.286-0.862; p = 0.013) was lower in HUK group than non-HUK group. This association was consistent with propensity score-matching and the inverse probability of treatment weighting analysis. In conclusion, HUK was safe and associated with a preferable prognosis in AIS patients due to LVO in the anterior circulation.

Dyslipidemia versus obesity as predictors of ischemic stroke prognosis: a multi-center study in China

BACKGROUND

This multicenter observational study aimed to determine whether dyslipidemia or obesity contributes more significantly to unfavorable clinical outcomes in patients experiencing a first-ever ischemic stroke (IS).

METHODS

The study employed a machine learning predictive model to investigate associations among body mass index (BMI), body fat percentage (BFP), high-density lipoprotein (HDL), triglycerides (TG), and total cholesterol (TC) with adverse outcomes in IS patients. Extensive real-world clinical data was utilized, and risk factors significantly linked to adverse outcomes were identified through multivariate analysis, propensity score matching (PSM), and regression discontinuity design (RDD) techniques. Furthermore, these findings were validated via a nationwide multicenter prospective cohort study.

RESULTS

In the derived cohort, a total of 45,162 patients diagnosed with IS were assessed, with 522 experiencing adverse outcomes. A multifactorial analysis incorporating PSM and RDD methods identified TG (adjusted odds ratio (OR) = 1.110; 95% confidence interval (CI): 1.041-1.183; P <  0.01) and TC (adjusted OR = 1.139; 95%CI: 1.039-1.248; P <  0.01) as risk factors. However, BMI, BFP, and HDL showed no significant effect. In the validation cohort, 1410 controls and 941 patients were enrolled, confirming that lipid levels are more strongly correlated with the prognosis of IS patients compared to obesity (TC, OR = 1.369; 95%CI: 1.069-1.754; P <  0.05; TG, OR = 1.332; 95%CI: 1.097-1.618; P <  0.01).

CONCLUSION

This study suggests that dyslipidemia has a more substantial impact on the prognosis of IS patients compared to obesity. This highlights the importance of prioritizing dyslipidemia management in the treatment and prevention of adverse outcomes in IS patients.

Decreased Tissue Kallikrein Levels and the Risk of Ischemic Stroke: A Community-Based Cross-Sectional Study in China

Aim

Tissue kallikrein (TK) exerts protective effects on cardiac cerebrovascular diseases (CCVDs). Changes in TK level in plasma are associated with ischemic stroke and coronary artery disease (CAD); however, a causal correlation could not be established. Therefore, we investigated the association between TK levels and CCVDs in a community-based cross-sectional study in China.

Methods

A total of 6043 subjects (4242 men and 1801 women) were enrolled in this community-based cross-sectional study. Then, TK levels were measured using an enzyme-linked immunosorbent assay kit. Multivariate linear regression model and logistic regression were used to assess the correlations between TK levels and CCVDs. Subsequently, the receiver operating characteristic (ROC) curve was drawn to assess the value of TK level in evaluating the risk of ischemic stroke. Finally, the influence of various medications was evaluated on TK levels.

Results

The TK level was significantly lower in subjects with ischemic stroke (P < 0.001) and hypertension (P < 0.001) and negatively associated with ischemic stroke (P < 0.001) but not associated with hypertension, coronary heart disease, and diabetes compared to the traditional risk factors. The diagnostic accuracy for ischemic stroke, as quantified by the area under the curve, was 0.892 (95% CI, 0.884–0.900) for TK level, deeming it as a promising assessment tool. Moreover, no appreciable influence of various drugs therapy was found in TK levels (P = 0.222) except for those taking antilipemic agents.

Conclusion

TK is a strong and independent endogenous protective factor against ischemic stroke in the Chinese population and could be a promising biomarker for the risk of ischemic stroke.

Increase in Blood-Brain Barrier Permeability is Modulated by Tissue Kallikrein via Activation of Bradykinin B1 and B2 Receptor-Mediated Signaling

Aim

Disruption of the blood–brain barrier (BBB) is a critical pathological feature after stroke. Although tissue kallikrein (TK) has used in the treatment of stroke in China, the role of TK in modulating BBB permeability is not clear.

Methods

We investigated the effect of different doses of TK on BBB by in vivo assessments of Evans blue (EB) and sodium-fluorescein isothiocyanate (FITC) leakage and in vitro assessments of the integrity of BBB and monolayers of microvascular endothelial cells (BMVECs). The expression of zonula occludens-1 (ZO-1) and bradykinin receptor-mediated signaling in BMVECs was detected.

Results

A significant increase in BBB permeability was observed in the mice treated with high dose of TK. However, standard and medium doses of TK could only enable sodium-FITC to enter the brain. The result of in vitro study indicated that high-doses of TK, but not standard and medium-dose of TK, reduced normal BBB integrity accompanied by a decreased expression of zonula occludens-1 (ZO-1), upregulated the mRNA levels of bradykinin 2 receptor (B2R) and endothelial nitric oxide synthase (eNOS) and the abundance of B2R. Moreover, standard-dose of TK exacerbated lipopolysaccharide-induced BBB hyperpermeability, upregulated the mRNA levels of bradykinin 1 receptor (B1R) and inducible nitric oxide synthase (iNOS), increased the abundance of B1R and reduced the abundance of ZO-1; these effects were inhibited by TK inhibitor.

Conclusion

TK can disrupt tight junctions and increase normal BBB permeability via B2R-dependent eNOS signaling pathway, aggravate impairment of BBB via B1R-dependent iNOS signaling pathway, and consequently serve as a useful adjunctive treatment for enhancing the efficacy of other neurotherapeutics.

Tissue Kallikrein Exacerbating Sepsis-Induced Endothelial Hyperpermeability is Highly Predictive of Severity and Mortality in Sepsis

Aim

Sepsis, an acute, life-threatening dysregulated response to infection, affects practically all aspects of endothelial function. Tissue kallikrein (TK) is a key enzyme in the kallikrein–kinin system (KKS) which has been implicated in endothelial permeability. Thus, we aimed to establish a potentially novel association among TK, endothelial permeability, and sepsis demonstrated by clinical investigation and in vitro studies.

Methods

We performed a clinical investigation with the participation of a total of 76 controls, 42 systemic inflammatory response syndrome (SIRS) patients, and 150 patients with sepsis, who were followed-up for 28 days. Circulating TK levels were measured with an enzyme-linked immunosorbent assay. Then, the effect of TK on sepsis-induced endothelial hyperpermeability was evaluated by in vitro study.

Results

Data showed a gradual increase in TK level among controls and the patients with SIRS, sepsis, and septic shock (0.288±0.097 mg/l vs 0.335±0.149 vs 0.495±0.170 vs 0.531±0.188 mg/l, respectively, P <0.001). Further analysis revealed that plasma TK level was positively associated with the severity and mortality of sepsis and negatively associated with event-free survival during 28 days of follow-up (relative risk, 3.333; 95% CI, 2.255–4.925; p < 0.001). With a septic model of TK and kallistatin in vitro, we found that TK exacerbated sepsis-induced endothelial hyperpermeability by downregulating zonula occluden-1 (ZO-1) and vascular endothelial (VE)-cadherin, and these could be reversed by kallistatin, an inhibitor of TK.

Conclusion

TK can be used in the diagnosis of sepsis and assessment of severity and prognosis of disease. Inhibition of TK may be a novel therapeutic target for sepsis through increasing ZO-1 and VE-cadherin, as well as downregulating endothelial permeability.

Serum Interleukin-37 Increases in Patients after Ischemic Stroke and Is Associated with Stroke Recurrence

Background

This study seeks to assess interleukin-37 (IL-37) serum level in acute ischemic stroke and the value of predicting 3-month stroke recurrence and functional outcome in acute ischemic stroke.

Methods

From January 1, 2018, to June 30, 2019, all consecutive first-ever acute ischemic stroke patients from our hospital, China, were included. Serum samples, clinical information, and stroke severity (defined by the National Institute of Health stroke scale (NIHSS) score) were collected at baseline. Serum IL-37 level was measured by the enzyme-linked immunosorbent assay (ELISA) method. Functional impairment (defined by the modified Rankin scale (mRS)) and recurrent stroke were assessed 3 months after admission. The relation of IL-37 with either clinical severity at baseline, unfavorable functional outcome, or stroke recurrence at follow-up was evaluated by logistic regression analysis, and the results were presented as odds ratios (OR) with 95% confidence intervals (CI).

Results

Three hundred and ten stroke patients were included. The median IL-37 serum level in those patients was 344.1 pg/ml (interquartile range (IQR), 284.4-405.3 vs. control cases: 122.3 pg/ml (IQR, 104.4-1444.0); P < 0.001). At 3 months, a total of 36 (11.6%) patients had a stroke recurrence. IL-37 serum levels in those patients were higher than in those patients without stroke recurrence (417.0 pg/ml (IQR, 359.3-436.1) vs. 333.3 pg/ml (279.0-391.0)). In a logistic model adjusted for other factors, IL-37 in the highest quartile (>405.3 pg/ml) was still associated with recurrent stroke (OR = 3.32; 95%CI = 2.03–6.13; P < 0.001). IL-37 could promote the NIHSS score (area under the curve (AUC) of the IL-37/NIHSS, 0.75; 95% CI, 0.67–0.83; P < 0.001), corresponding to a difference of 0.085 (0.005). Serum IL-37 increases in patients with poor outcome, and an IL-37 in the highest quartile is related to poor outcome (OR = 4.85; 95%CI = 3.11 − 8.22; P < 0.001).

Conclusion

Serum IL-37 increased in patients after ischemic stroke and was associated with stroke recurrence events and poor stroke outcomes. Large randomized controlled trials should be carried out to confirm whether IL-37 lowering treatment improves stroke prognosis.

High Level of Serum Tissue Kallikrein Is Associated with Favorable Outcome in Acute Ischemic Stroke Patients

Background/Objectives

We sought to assess the association between a serum tissue kallikrein (TK) level and a 90-day outcome in acute ischemic stroke (AIS) patients who received acute reperfusion therapy.

Methods

Consecutive AIS patients within 6 hours after stroke onset between December 2015 and August 2017 were prospectively recruited. Blood samples were collected before acute reperfusion therapy for serum TK measurement. Outcome was modified Rankin scale (mRS) score at 90 days after stroke onset. Binary logistic regression was performed to analyze the association between the baseline TK level and the clinical outcome.

Results

Between December 2015 and August 2017, 75 patients (age range from 33 to 91 years, 72.0% male) were recruited in this study. Higher baseline TK was independently associated with a favorable functional outcome (mRS 0-2) (odds ratio 1.01, 95% confidence interval (CI) 1.00-1.02, p = 0.047) and low mortality rate (odds ratio 0.98, 95% CI 0.96-1.00, p = 0.049) at 90 days. Increased TK level was associated with 90 d mRS (0-2) with area under the curve of 0.719 (95% CI 0.596-0.842; p = 0.002).

Conclusions

Serum TK can be a promising predictor of clinical outcome in AIS patients who received acute reperfusion therapy.

Serum fatty acid binding protein 4 is positively associated with early stroke recurrence in nondiabetic ischemic stroke

Adipocyte fatty acid–binding protein (FABP4) played critical roles in metabolic syndrome, inflammatory responses and cardiovascular diseases. It aimed to investigate the associations of serum FABP4 levels with early stroke recurrence. This study included the 206 acute ischemic stroke patients hospitalized in our institution. Stroke recurrence events were assessed at the 3-month follow-up. The median of FABP level was 22.6 (IQR, 17.9-31.6) ng/mL in patients with stroke recurrence (N=36), which was higher than in patients without stroke recurrence [16.9 (IQR, 11.8-21.4) ng/mL] (P<0.001). As a continuous variable, the unadjusted and adjusted risk of stroke recurrence would be increased by 12% (OR=1.12 [95% CI 1.06–1.17], P<0.001) and 8% (1.08 [1.02–1.14], P=0.006) for every 1 ng/ml increment of FABP4. The Area under the curve (AUC) of serum FABP4 and NIH Stroke Scale (NIHSS) score for predicting stroke recurrence was 0.73 (95% CI: 0.64–0.82) and 0.72 (95% CI: 0.64–0.81), presenting no discriminating capacity (P=0.45). In the combining model, the AUC of NIHSS score was further improved to 0.77 by FABP4 (0.77; 95% CI: 0.69–0.85), which was significant (P=0.01). The risk of stroke recurrence can be predicted by elevated FABP4 levels in serum of nondiabetic patients with first-ever ischemic stroke.

Therapeutic Values of Human Urinary Kallidinogenase on Cerebrovascular Diseases

The term “tissue kallikrein” is used to describe a group of serine proteases shared considerable sequence homology and colocalize in the same chromosomal locus 19q13. 2–q13.4. It has been widely discovered in various tissues and has been proved to be involved in kinds of pathophysiological processes, such as inhibiting oxidative stress, inflammation, apoptosis, fibrosis and promoting angiogenesis, and neurogenesis. Human Urinary Kallidinogenase (HUK) extracted from human urine is a member of tissue kallikrein which could convert kininogen to kinin and hence improve the plasma kinin level. Medical value of HUK has been widely investigated in China, especially on acute ischemic stroke. In this review, we will summarize the therapeutic values of Human Urinary Kallidinogenase on acute ischemic stroke and its potential mechanisms.

Implication of the Kallikrein-Kinin system in neurological disorders: Quest for potential biomarkers and mechanisms

Neurological disorders represent major health concerns in terms of comorbidity and mortality worldwide. Despite a tremendous increase in our understanding of the pathophysiological processes involved in disease progression and prevention, the accumulated knowledge so far resulted in relatively moderate translational benefits in terms of therapeutic interventions and enhanced clinical outcomes. Aiming at specific neural molecular pathways, different strategies have been geared to target the development and progression of such disorders. The kallikrein-kinin system (KKS) is among the most delineated candidate systems due to its ubiquitous roles mediating several of the pathophysiological features of these neurological disorders as well as being implicated in regulating various brain functions. Several experimental KKS models revealed that the inhibition or stimulation of the two receptors of the KKS system (B1R and B2R) can exhibit neuroprotective and/or adverse pathological outcomes. This updated review provides background details of the KKS components and their functions in different neurological disorders including temporal lobe epilepsy, traumatic brain injury, stroke, spinal cord injury, Alzheimer's disease, multiple sclerosis and glioma. Finally, this work will highlight the putative roles of the KKS components as potential neurotherapeutic targets and provide future perspectives on the possibility of translating these findings into potential clinical biomarkers in neurological disease.

Serum Copeptin Predicts Severity and Recurrent Stroke in Ischemic Stroke Patients

Several studies investigated the prognostic role of copeptin in stroke. The aim of this study is to assess copeptin levels in serum, and investigate their associations with risk of recurrent stroke in a 1-year follow-up study in patients with ischemic stroke. In this post hoc analysis, serum levels of copeptin and NIH stroke scale (NIHSS) were measured at the time of admission in a cohort of 316 patients with ischemic stroke. The end point was stroke recurrence after 1-year follow-up. We used logistic regression model to assess the relationship between copeptin levels and risk recurrent stroke. Logistic regression analysis considering traditional risk factors showed a relationship between serum copeptin levels and moderate-to-high clinical severity when serum copeptin was used as a continuous variable (OR, 1.05; 95% CI, 1.03-1.09). In the follow-up, 54 patients (17.1%) had a stroke recurrence. The stroke recurrence events distribution across the copeptin quartiles ranged between 5.1% (first quartile) to 23.1% (fourth quartile). In multivariate models comparing the third (OR = 2.78; 95% CI 1.85-3.53) and fourth quartiles (OR = 4.00; 95% CI 2.86-6.50) against the first quartile of the copeptin, levels of copeptin were associated with stroke recurrence events. A higher serum copeptin level is a predictor of both severity at admission and stroke recurrence at 1-year in stroke patients.

Vitamin D Status and the Risk of Recurrent Stroke and Mortality in Ischemic Stroke Patients: Data from a 24-Month Follow-Up Study in China

PURPOSE

In this study, we determined serum 25-hydroxyvitamin D [25(OH) D] levels in serum, and investigated their associations with risk of recurrent stroke and mortality in a 24-month follow up study in Chinese patients with first-ever ischemic stroke.

METHODS

In this preplanned post hoc analysis, serum levels of 25(OH) D and NIH stroke scale (NIHSS) were measured at the time of admission in a cohort of patients with ischemic stroke. We used logistic regression model to assess the relationship between 25(OH) D levels and risk recurrent stroke or mortality.

RESULTS

The follow-up rate was 98.2% in 220 stroke patients. Of 216 patients, 18.5% (95%CI: 13.3%-23.7%) patients had a stroke recurrence, and 30.1% (95% CI: 24.0%-36.2%) died. After adjustment for traditional risk factors, serum 25(OH) D levels were negatively associated with the risk of stroke recurrence (odds ratio [OR], 0.77; 95% confidence interval [CI], 0.70-0.85; P < 0.001) and negatively associated with mortality during 24 months of follow-up (OR, 0.72; 95% CI, 0.64-0.80; P< 0.001). Compared with the first quartile of serum 25(OH) D levels, the ORs for stroke recurrence and mortality were as follows: second quartile, 0.80 (95% CI, 0.63-0.93) and 0.77 (95% CI, 0.65-0.89); third quartile, 0.42 (95% CI, 0.31-0.55) and 0.39 (95% CI, 0.30-0.52); fourth quartile, 0.12 (95% CI, 0.07-0.19) and 0.10 (95% CI, 0.06-0.15), respectively.

CONCLUSIONS

Lower serum levels of 25(OH) D are independently associated with the stroke recurrence and mortality at 24 months in ischemic stroke patients.

Serum 25-hydroxyvitamin D predicts early recurrent stroke in ischemic stroke patients

BACKGROUND AND AIM

This study was conducted to determine 25-hydroxyvitamin D [25(OH) D] levels in serum, and to investigate their associations with stroke recurrence events in a 3-month follow-up study in Chinese patients with first-ever ischemic stroke.

METHODS AND RESULTS

From February 2014 to September 2015, consecutive first-ever ischemic stroke patients admitted to the Department of Emergency of our hospital were identified. Serum 25(OH) D levels were measured at admission. We followed the participants for a median of 3 months (range, 2.5-3.5 months) using a standard questionnaire. We used logistic regression models to assess the relationship between 25(OH) levels and risk of recurrent stroke. In this study, 349 ischemic stroke patients were included and completed follow-up. Thirty-seven patients (10.6%) had a stroke recurrence. Serum 25(OH) D levels in patients with recurrent stroke were significantly lower as compared with those in patients without recurrent stroke [9.9 (IQR, 7.9-14.8) ng/mL vs. 17.9 (IQR, 13.4-23.4) ng/mL; P < 0.001). After adjusting for traditional risk factors, serum 25(OH) D levels were negatively associated with the stroke recurrence (OR, 0.897; 95% CI, 0.848-0.950; P < 0.001). Compared with the first quartile of serum 25(OH) D levels, the second quartile OR for recurrent stroke was 0.466 (95% CI, 0.308-707; P = 0.006). For the third and fourth quartiles, it was 0.248 (95% CI, 0.100-0.618; P = 0.001) and 0.173 (95% CI, 0.062-0.482; P < 0.001), respectively.

CONCLUSIONS

Our findings suggest that reduced serum levels of 25(OH) D can predict the risk of early stroke recurrence in patients with first-ever ischemic stroke.

Tissue Kallikrein Prevents Restenosis After Stenting of Severe Atherosclerotic Stenosis of the Middle Cerebral Artery: A Randomized Controlled Trial

In-stent restenosis (ISR) following intracranial artery stenting affects long-term clinical outcome. This randomized controlled trial sought to identify the long-term efficacy of exogenous tissue kallikrein (TK) for preventing ISR after intracranial stenting of symptomatic middle cerebral artery (MCA) atherosclerotic stenosis.Sixty-one patients successfully treated with intracranial stenting for symptomatic MCA M1 segment stenosis (>70%) were enrolled and randomized into 2 groups: control group and TK group. Patients in the TK group received human urinary kallidinogenase for 7 days, followed by maintenance therapy of pancreatic kallikrein for 6 months. The primary end point was angiographically verified ISR at 6 months, and secondary end points included vascular events and death within 12 months. Endogenous TK plasma concentrations of patients were measured before stenting and at the 6-month follow-up time-point.Patients in the TK group had lower occurrence rates of ISR and vascular events than patients in the control group. There was no difference in endogenous TK levels in plasma at 6 months postoperatively between the TK and control groups. Further subgroup analysis revealed that patients without ISR had higher endogenous TK levels at baseline and lower concentrations at 6 months postoperatively compared with patients who underwent ISR.Exogenous TK is effective for the prevention of ISR after intracranial stenting.

Tissue Kallikrein Activity, Detected by a Novel Method, May Be a Predictor of Recurrent Stroke: A Case-Control Study

Aim. Tissue kallikrein (TK) protein content in plasma has been shown to be negatively associated with both incident and recurrent strokes. The aims of this study were to develop a novel method for detecting TK activity and to investigate its association with event-free survival over 5 years in Chinese first-ever stroke patients. Methods. We designed a case-control study with 321 stroke patients (174: ischemic stroke, 147: hemorrhagic stroke) and 323 healthy local controls. TK activity was measured by a novel assay utilizing the immunological characteristics of TK and the catalysis of benzoyl arginine ethyl ester hydrochloride (BAEE). Results. TK protein levels above 0.200 mg/L in plasma were not associated with urinary TK activity or the risk of stroke recurrence. TK activity was significantly lower in stroke patients compared with controls (1.583 ± 0.673 Eu/mL versus 1.934 ± 0.284 Eu/mL, P < 0.001). After adjusting for traditional risk factors, TK activity was negatively associated, in a dose-response manner, with the risk of overall stroke recurrence and positively associated with event-free survival during a 5-year follow-up (relative risk (RR), 0.69; 95% CI, 0.57–0.84; P < 0.001). Conclusions. Our findings suggest that urinary TK activity may be a stronger predictor of stroke recurrence than plasma TK levels.

Human urine kininogenase attenuates balloon-induced intimal hyperplasia in rabbit carotid artery through transforming growth factor β1/Smad2/3 signaling pathway

OBJECTIVE

Effective treatments against restenosis after percutaneous transluminal angioplasty and stenting are largely lacking. Human tissue kallikrein gene transfer has been shown to be able to attenuate neointima formation induced by balloon catheter. As a tissue kallikrein in vivo, human urinary kininogenase (HUK) is widely used to prevent ischemia-reperfusion injury. However, the effects of HUK on neointima formation have not been explored. We therefore investigated whether HUK could alleviate balloon catheter-induced intimal hyperplasia in rabbits fed with high-fat diets.

METHODS

The effects of HUK on neointima and atherosclerosis formation were analyzed by hematoxylin-eosin staining and immunohistochemical staining in balloon-injured carotid arteries of rabbits. Local inflammatory response was evaluated by detecting the gene expression of tumor necrosis factor α and interleukin 1β with real-time quantitative polymerase chain reaction plus the invasion of macrophages with immunohistochemical staining. Western blotting was employed to investigate the effects of HUK on activities of endothelial nitric oxide synthase (eNOS), transforming growth factor β1 (TGF-β1), and Smad signaling pathway. The long-term effect of HUK on intimal hyperplasia of the injured carotid artery was assessed by angiography.

RESULTS

Quantitative image analysis showed that intravenous administration of HUK for 14 days significantly decreased the intimal areas and intima area/media area ratios (day 14, 54% decrease in intimal area and 58% decrease in intima area/media area ratios; day 28, 63% and 85%). Significant decreases were also noted in macrophage foam cell-positive area after 7-day or 14-day administration of HUK (day 7, 69% decrease in intimal area and 78% decrease in media area; day 14, 79% and 60%; day 28, 68% and 44%). Actin staining for smooth muscle cells in neointima at 2 months showed similar results (vascular smooth muscle cell-positive area of neointima, 28.21% ± 5.58% vs 43.78% ± 8.36%; P < .05). Real-time quantitative polymerase chain reaction or Western blot analysis showed that HUK reduced expression of tumor necrosis factor α, interleukin 1β, TGF-β1, and p-Smad2/3 but increased the expression of p-eNOS. Angiography analysis showed that 14-day administration of HUK significantly decreased the degree of stenosis (26.8% ± 7.1% vs 47.9% ± 5.7%; P < .01) at 2 months after balloon injury.

CONCLUSIONS

Our results indicate that HUK is able to attenuate atherosclerosis formation and to inhibit intimal hyperplasia by downregulating TGF-β1 expression and Smad2/3 phosphorylation, upregulating eNOS activity. HUK may be a potential therapeutic agent to prevent stenosis after vascular injury.

Identification of circulating microRNAs as potential biomarkers for detecting acute ischemic stroke

MicroRNAs (miRNAs) are present in serum and have the potential to serve as disease biomarkers. As such, it is important to explore the clinical value of miRNAs in serum as biomarkers for ischemic stroke (IS) and cast light on the pathogenesis of IS. In this study, we screened differentially expressed serum miRNAs from IS and normal people by miRNA microarray analysis, and validated the expression of candidate miRNAs using quantitative reverse-transcriptase polymerase chain reaction assays. Furthermore, we performed gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses to disclose functional enrichment of genes predicted to be regulated by the differentially expressed miRNAs. Notably, our results revealed that 115 miRNAs were differentially expressed in IS, among which miR-32-3p, miR-106-5p, and miR-532-5p were first found to be associated with IS. In addition, GO and KEGG pathway analyses showed that genes predicted to be regulated by differentially expressed miRNAs were significantly enriched in several related biological process and pathways, including axon guidance, glioma, MAPK signaling, mammalian target of rapamycin signaling, and ErbB-signaling pathway. In conclusion, we identified the changed expression pattern of miRNAs in IS. Serum miR-32-3p, miR-106-5p, miR-1246, and miR-532-5p may serve as potential diagnostic biomarkers for IS. Our results also demonstrate a novel role for miRNAs in the pathogenesis of IS.

Relation of plasma tissue kallikrein levels to presence and severity of coronary artery disease in a Chinese population

Objectives

Tissue kallikrein (TK) has been shown to provide cardiovascular and cerebrovascular protective effects in animal models. The aim of this study was to investigate the relationship of plasma TK levels with the presence and severity of coronary artery disease (CAD) in the Chinese.

Methods

The study involved 898 consecutive CAD patients and 905 ethnically and geographically matched controls. CAD was angiographically confirmed in all the patients, and the severity of CAD was expressed by the number of affected vessel and coronary artery stenosis scores. Plasma TK levels were measured using an enzyme-linked immunosorbent assay.

Results

Plasma TK levels were significantly higher in CAD patients than controls (0.347±.082 vs. 0.256±0.087 mg/L, P<0.001), and elevated plasma TK levels were directly associated with a higher risk of CAD (OR = 3.49, 95% CI 2.90–4.19). One-way ANOVA and multivariable stepwise linear regression analysis demonstrated that TK levels were negatively associated with the severity of CAD according to vessel scores (P<0.001) and stenosis scores (r = −0.211, p<0.001).

Conclusions

Our findings suggest that higher levels of TK in plasma are associated with the presence of CAD and are a predictor of mild coronary arteriosclerosis.

Circulating miR-30a, miR-126 and let-7b as biomarker for ischemic stroke in humans

Background

Recently, plasma miRNAs have been reported as biomarkers for various diseases. However, the knowledge on the association of plasma miRNAs with ischemic stroke is still lacking. In this study, we investigated whether plasma concentrations of miR-30a, miR-126 and let-7b may be biomarkers for ischemic stroke in humans.

Methods

One hundred ninety seven patients with ischemic stroke were recruited and their blood samples were collected at 24 h, 1 week, 4 weeks, 24 weeks and 48 weeks after symptoms onset, and fifty healthy volunteers were selected as control. Levels of miRNA were quantified by quantitative real-time PCR. Relative expression level of miRNA was calculated using 2^-ΔΔct method. The ability to distinguish the ischemic stroke group from control group was characterized by receiver operating characteristic (ROC) curve, and the area under ROC curve (AUC) was calculated.

Results

Circulating miR-30a and miR-126 levels were markedly down-regulated in all patients with ischemic stroke until 24 weeks. However, circulating let-7b was lower in patients with large-vessel atherosclerosis than healthy volunteers, whereas circulating let-7b had higher level in patients with other kinds of ischemic stroke until 24 weeks. Among all patients, circulating miRNAs levels returned to normal 48 weeks after symptom onset. Receiver operating characteristic (ROC) curve analysis showed that the areas under the curve (AUC) of plasma miR-30a were 0.91, 0.91, 0.92 and 0.93, the miR-126 were 0.92, 0.94, 0.93 and 0.92, and let-7b were 0.93, 0.92, 0.92 and 0.91 at 24 h, 1 w, 4 w and 24 w, respectively.

Conclusions

These data suggest that miR-30a, miR-126 and let-7b might be useful biomarkers for ischemic stroke in humans.