Minocycline and tissue-type plasminogen activator for stroke: assessment of interaction potential.
OBJECTIVE
New treatment strategies for acute ischemic stroke must be evaluated in the context of effective reperfusion. Minocycline is a neuroprotective agent that inhibits proteolytic enzymes and therefore could potentially both inactivate the clot lysis effect and decrease the damaging effects of tissue-type plasminogen activator (t-PA). This study aimed to determine the effect of minocycline on t-PA clot lysis and t-PA-induced hemorrhage formation after ischemia.


METHODS
Fibrinolytic and amidolytic activities of t-PA were investigated in vitro over a range of clinically relevant minocycline concentrations. A suture occlusion model of 3-hour temporary cerebral ischemia in rats treated with t-PA and 2 different minocycline regimens was used. Blood-brain barrier basal lamina components, matrix metalloproteinases (MMPs), hemorrhage formation, infarct size, edema, and behavior outcome were assessed.


RESULTS
Minocycline did not affect t-PA fibrinolysis. However, minocycline treatment at 3 mg/kg IV decreased total protein expression of both MMP-2 (P=0.0034) and MMP-9 (P=0.001 for 92 kDa and P=0.0084 for 87 kDa). It also decreased the incidence of hemorrhage (P=0.019), improved neurologic outcome (P=0.0001 for Bederson score and P=0.0391 for paw grasp test), and appeared to decrease mortality. MMP inhibition was associated with decreased degradation in collagen IV and laminin-alpha1 (P=0.0001).


CONCLUSIONS
Combination treatment with minocycline is beneficial in t-PA-treated animals and does not compromise clot lysis. These results also suggest that neurovascular protection by minocycline after stroke may involve direct protection of the blood-brain barrier during thrombolysis with t-PA.
Machado
Livia S
LS
Department of Clinical and Administrative Pharmacy, University of Georgia College of Pharmacy, Augusta, GA 30912-2450, USA.
Sazonova
Irina Y
IY
Kozak
Anna
A
Wiley
Daniel C
DC
El-Remessy
Azza B
AB
Ergul
Adviye
A
Hess
David C
DC
Waller
Jennifer L
JL
Fagan
Susan C
SC
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001812:Blood-Brain Barrier / Q000378:metabolism; D002545:Brain Ischemia / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D002543:Cerebral Hemorrhage / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism; D004353:Drug Evaluation, Preclinical; D005342:Fibrinolysis / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis; D008911:Minocycline / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D020521:Stroke / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000009:adverse effects* / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D018696:Neuroprotective Agents; D010959:Tissue Plasminogen Activator; D020778:Matrix Metalloproteinase 2; C522363:Mmp2 protein, rat; D020780:Matrix Metalloproteinase 9; D008911:Minocycline