title: Tissue Kallikrein Activity, Detected by a Novel Method, May Be a Predictor of Recurrent Stroke: A Case-Control Study.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Emergency Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue No. 1095, Wuhan 430030, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Ran
authors.affiliation: Department of Anesthesia, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue No. 1095, Wuhan 430030, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: The Institute of Hypertension and Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Jiefang Avenue No. 1095, Wuhan 430030, China.
authors.forename: Dao Wen
authors.initials: DW
authors.lastname: Wang
mesh_terms: D000368:Aged; D001120:Arginine / Q000031:analogs & derivatives / Q000737:chemistry; D015415:Biomarkers / Q000097:blood / Q000652:urine; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D020521:Stroke / Q000097:blood / Q000652:urine*; D020840:Tissue Kallikreins / Q000097:blood / Q000652:urine*; D016482:Urinalysis / Q000379:methods
chemical_list: D015415:Biomarkers; D001120:Arginine; C009727:benzoylarginine ethyl ester; D020840:Tissue Kallikreins