Activated protein C therapy in a rat heat stroke model.

Abstract

OBJECTIVE:

To evaluate the therapeutic effects of activated protein C in an animal model of heat stroke.

DESIGN:

Laboratory investigation.

SETTING:

Chi-Mei Medical Center research laboratory.

SUBJECTS:

Male Sprague-Dawley rats weighing 252-304 g.

INTERVENTIONS:

Anesthetized animals were subjected to heat stress (40 degrees C) to induce heat stroke. A bolus injection of normal saline or recombinant human activated protein C (drotrecogin alfa, activated) was conducted via femoral catheters immediately after the onset of heat stroke. Blood sampling was done before initiation of heat stress and 0 and 40 mins after the onset of heat stroke.

MEASUREMENTS AND MAIN RESULTS:

When the vehicle-treated rats underwent heat exposure, their survival time values were found to be 56-64 mins (n = 16). Resuscitation with activated protein C significantly and dose-dependently improved survival during heat stroke (108-246 mins for doses of 0.5-20 mg of activated protein C per kilogram of body weight) (n = 32). All heat-stressed animals displayed systemic inflammation and activated coagulation, evidenced by increased tumor necrosis factor-alpha, prothrombin time, activated partial thromboplastin time, and D-dimer and decreased platelet count and protein C. Biochemical markers evidenced by cellular ischemia and injury/dysfunction included increased plasma levels of blood urea nitrogen, creatinine, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and alkaline phosphatase; increased striatal levels of glutamate, glycerol, and lactate/pyruvate ratio; and decreased striatal levels of partial pressure of oxygen and local cerebral blood flow, which were all observed during heat stroke. These heat stroke reactions were all significantly suppressed by resuscitation with activated protein C but not vehicle solution.

CONCLUSIONS:

The results indicate that systemic delivery of human recombinant activated protein C at the time point of onset of heat stroke may improve survival by ameliorating systemic inflammation, hypercoagulable state, and tissue ischemia and injury in multiple organs.

• Authors: Chin-Ming Chen, Ching-Cheng Hou, Kuo-Chen Cheng, Ru-Ling Tian, Ching-Ping Chang, Mao-Tsun Lin
• Journal: Critical care medicine (Crit Care Med) Vol. 34 Issue 7 Pg. 1960-6 (Jul 2006) ISSN: 0090-3493 [Print] United States
• PMID: 16715032 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Fibrin Fibrinogen Degradation Products
• Lactates
• Protein C
• Pyruvates
• Recombinant Proteins
• Tumor Necrosis Factor-alpha
• fibrin fragment D
• Glutamic Acid
• Creatinine
• Transaminases
• Alkaline Phosphatase
• Glycerol
• Oxygen

Topics

• Alkaline Phosphatase (blood)
• Animals
• Blood Urea Nitrogen
• Cerebrovascular Circulation
• Creatinine (blood)
• Disease Models, Animal
• Dose-Response Relationship, Drug
• Fibrin Fibrinogen Degradation Products (analysis)
• Glutamic Acid (blood)
• Glycerol (blood)
• Heat Stroke (blood, drug therapy, physiopathology)
• Lactates (blood)
• Male
• Oxygen (blood)
• Partial Pressure
• Partial Thromboplastin Time
• Platelet Count
• Protein C (administration & dosage, analysis, therapeutic use)
• Prothrombin Time
• Pyruvates (blood)
• Rats
• Rats, Sprague-Dawley
• Recombinant Proteins (administration & dosage, therapeutic use)
• Regional Blood Flow
• Transaminases (blood)
• Tumor Necrosis Factor-alpha (analysis)