Human umbilical cord blood-derived CD34+ cells cause attenuation of multiorgan dysfunction during experimental heatstroke.

Multiorgan dysfunction ensuing from severe heatstroke includes hypotension, hepatic and renal failure, hypercoagulable state, activated inflammation, and cerebral ischemia and injury. We attempted to assess whether human umbilical cord bloodYderived CD34 + cell therapy improves survival during experimental heatstroke by attenuating multiorgan dysfunction. Anesthetized rats, immediately after the onset of heatstroke, were divided into 2 major groups and given CD34 j or CD34 + cells (1 � 10 5 Y 5 � 10 5 /mL/kg body weight) i.v. They were exposed to ambient temperature of 43-C to induce heatstroke. Another group of rats were exposed to room temperature (26-C) and used as normothermic controls. Hypotension, hepatic and renal failure (evidenced by increased serum urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase levels in plasma), hypercoagulable state (evidenced by increased prothrombin time, activated partial thromboplastin time, and D-dimer, and decreased platelet count and protein C in plasma), activated inflammation (evidence by increased TNF-! levels in serum), and cerebral dysfunction (evidenced by intracranial hypertension, cerebral hypoperfusion and hypoxia, and cerebral ischemia and injury) were monitored. When the CD34 j cellYtreated or untreated rats underwent heat stress, their survival time values were found to be 19 to 23 min. Resuscitation with CD34 + cells significantly improved survival time (duration, 63 Y 291 min). As compared with normothermic controls, all CD34 j cellYtreated heatstroke animals displayed hypotension, hepatic and renal failure, hypercoagulable state, activated inflammation, and cerebral ischemia and injury. However, CD34 + cell therapy significantly caused attenuation of all the above-mentioned heatstroke reactions. In addition, the levels of IL-10 in plasma and glial cell lineYderived neurotrophic factors in brain were all significantly increased after CD34 + cell therapy during heatstroke. Our data indicate that CD34 + cell therapy may resuscitate persons who had a heatstroke by reducing multiorgan dysfunction or failure. KEYWORDS—Heatstroke, blood pressure, cytokines, coagulation, umbilical cord blood cells