Mao-Tsun Lin

Hypoxic preconditioning enhances the therapeutic potential of the secretome from cultured human mesenchymal stem cells in experimental traumatic brain injury.

Bone-marrow-derived human MSCs (mesenchymal stem cells) support repair when administered to animals with TBI (traumatic brain injury) in large part through secreted trophic factors. We directly tested the ability of the culture medium (or secretome) collected from human MSCs under normoxic or hypoxic conditions to protect neurons in a rat model of TBI. Concentrated conditioned medium from cultured human MSCs or control medium was infused through the tail vein of rats subjected to TBI. We have demonstrated that MSCs cultured in hypoxia were superior to those cultured in normoxia in inducing expression of both HGF (hepatocyte growth factor) and VEGF (vascular endothelial growth factor) in the cultured medium. We showed further that rats treated with the secretome from both normoxic- and hypoxic-preconditioned MSCs performed significantly better than the controls in both motor and cognitive functional test. Subsequent post-mortem evaluation of brain damage at the 4-day time point confirmed that both normoxic- and hypoxic-preconditioned MSC secretome-treated rats had significantly greater numbers of newly forming neurons, but significantly less than the controls in brain damaged volume and apoptosis. The TBI rats treated with hypoxic-preconditioned MSC secretome performed significantly better in both motor and cognitive function tests and neurogenesis, and had significantly less brain damage than the TBI rats treated with the normoxic-preconditioned MSC secretome. Collectively, these findings suggest that MSCs secrete bioactive factors, including HGF and VEGF, that stimulate neurogenesis and improve outcomes of TBI in a rat model. Hypoxic preconditioning enhances the secretion of these bioactive factors from the MSCs and the therapeutic potential of the cultured MSC secretome in experimental TBI.

Hypothalamic dopamine release and local cerebral blood flow during onset of heatstroke in rats.

Background and Purpose Brain dopamine has been implicated as a mediator of brain neuronal damage resulting from ischemic injury. Augmented interleukin-1 production and cerebral ischemia occurred during onset of heatstroke. This study has attempted to ascertain whether heatstroke resulting from hyperthermia causes an increase in hypothalamic dopamine release and to assess whether the administration of an interleukin-1 receptor antagonist (IL-lra) can attenuate heatstroke formation. Methods Both local cerebral blood flow and hypothalamic dopamine release during onset of heatstroke were assessed in saline-treated rats and in rats treated with an IL-lra. Heatstroke was induced by exposing the animals to a high ambient temperature. Hypothalamic dopamine release was determined by carbon fiber electrodes combined with in vivo differential pulse amperometry. Results During onset of heatstroke, rats with heatstroke displayed higher values of colonic temperature, higher values of hypothalamic dopamine release, and lower values of blood flow in different brain regions compared with normothermic control rats. In another separate experiment in which IL-1ra (200 μg/kg IV) was injected 30 minutes before onset of heatstroke, both the augmented hypothalamic dopamine release and diminished cerebral blood flow during onset of heatstroke were significantly attenuated. In addition, the survival time (interval between onset of heatstroke and death) of the rats with heatstroke was prolonged by pretreatment with IL-lra. Conclusions These results suggest that an increase in hypothalamic dopamine release and a decrease in local cerebral blood flow occur during onset of heatstroke. Pretreatment with IL-lra attenuates the heatstroke formation resulting from cerebral ischemia by reducing hypothalamic dopamine release.

Small-dose dexamethasone reduces nausea and vomiting after laparoscopic cholecystectomy: A comparison of Tropisetron with saline

Dexamethasone is an effective antiemetic drug, but the efficacy of small-dose dexamethasone 5 mg on the prophylaxis of postoperative nausea and vomiting (PONV) in patients undergoing laparoscopic chole-cystectomy has not been evaluated. We, therefore, evaluated the prophylactic effect of small-dose dexamethasone (5 mg) on PONV in patients undergoing laparoscopic cholecystectomy. Tropisetron and saline served as controls. One-hundred-twenty patients scheduled for laparoscopic cholecystectomy were enrolled in a randomized, double-blinded, placebo-controlled study. At the induction of anesthesia, the Dexamethasone group received IV dexamethasone 5 mg, the Tropisetron group received IV tropisetron 2 mg, and the Pla- cebo group received IV saline. We found that both dexamethasone and tropisetron significantly decreased the following variables: the total incidence of PONV (P < 0.01), more than four vomiting episodes (P < 0.05), and the proportions of patients requiring rescue antiemetics (P < 0.05). The differences between the Dexamethasone and Tropisetron groups were not significant. We conclude that prophylactic IV dexamethasone 5 mg significantly reduces the incidence of PONV in patients undergoing laparoscopic cholecystectomy. At this dose, dexamethasone is as effective as tropisetron 2 mg and is more effective than placebo.

Brain cooling causes attenuation of cerebral oxidative stress, systemic inflammation, activated coagulation, and tissue ischemia/injury during heatstroke.

ABSTRACT The purpose of the present study was to assess the therapeutic effect of hypothermic retrograde jugular vein flush (HRJVF) on heatstroke. HRJVF was accomplished by infusion of 4°C isotonic sodium chloride solution via the external jugular vein (1.7 mL/100 g of body weight over 5 min). Immediately after the onset of heatstroke, anesthetized rats were divided into 2 major groups and given the following: 36°C or 4°C isotonic sodium chloride solution, i.v. They were exposed to ambient temperature of 43°C to induce heatstroke. Another group of rats was exposed to room temperature (24°C) and used as normothermic controls. When the 36°C saline-treated rats underwent heat exposure, their survival time values were found to be 23 to 28 min. Immediately after the onset of heatstroke, resuscitation with an i.v. dose of 4°C saline significantly improved survival during heatstroke (208-252 min). 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 cellular ischemia and injury/dysfunction: plasma levels of blood urea nitrogen, creatinine, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and alkaline phosphatase; and striatal levels of glycerol, glutamate, and lactate/pyruvate; dihydroxy benzoic acid, lipid peroxidation, oxidized-form glutathione reduced-form glutathione, dopamine, and serotonin were all elevated during heatstroke. Core and brain temperatures and intracranial pressure were also increased during heatstroke. In contrast, the values of mean arterial pressure, cerebral perfusion pressure, and striatal levels of local blood flow, partial pressure of oxygen, superoxide dismutase, catalase, glutathione peroxidase, and glutathions reductase activities were all significantly lower during heatstroke. The circulatory dysfunction, systemic inflammation, hypercoagulable state, and cerebral oxidative stress, ischemia, and damage during heatstroke were all significantly suppressed by HRJVF. These findings demonstrate that brain cooling caused by HRJVF therapy may resuscitate persons who had a stroke by attenuating cerebral oxidative stress, systemic inflammation, activated coagulation, and tissue ischemia/injury during heatstroke.

Human umbilical cord blood-derived CD34+ cells may attenuate spinal cord injury by stimulating vascular endothelial and neurotrophic factors.

Human umbilical cord blood-derived CD34+ cells were used to elucidate the mechanisms underlying the beneficial effects exerted by cord blood cells in spinal cord injury (SCI). Rats were divided into four groups: (1) sham operation (laminectomy only); (2) laminectomy + SCI + CD34− cells (5 × 105 human cord blood lymphocytes and monocytes that contained <0.2% CD34+ cells); (3) laminectomy + SCI + CD34+ cells (5 × 105 human cord blood lymphocytes and monocytes that contained ∼95% CD34+ cells); and (4) laminectomy + SCI + saline (0.3 mL). Spinal cord injury was induced by compressing the spinal cord for 1 min with an aneurysm clip calibrated to a closing pressure of 55 g. CD34 cells or saline was administered immediately after SCI via the tail vein. Behavioral tests of motor function measured by maximal angle an animal could hold to the inclined plane were conducted at days 1 to 7 after SCI. The triphenyltetrazolium chloride staining and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling assay were also conducted after SCI to evaluate spinal cord infarction and apoptosis, respectively. To elucidate whether glial cell line-derived neurotrophic factor (GDNF) or vascular endothelial growth factor (VEGF) can be secreted in spinal cord-injured area by the i.v. transplanted CD34+ cells, analysis of spinal cord homogenate supernatants by specific enzyme-linked immunosorbent assay for GDNF or immunofluorescence for VEGF was conducted. It was found that systemic administration of CD34+, but not CD34−, cells significantly attenuated the SCI-induced hind limb dysfunction and spinal cord infarction and apoptosis. Both GDNF and VEGF could be detected in the injured spinal cord after transplantation of CD34+, but not CD34−, cells. The results indicate that CD34+ cell therapy may be beneficial in reversing the SCI-induced spinal cord infarction and apoptosis and hindlimb dysfunction by stimulating the production of both VEGF and GDNF in a spinal cord compression model.

Intrathecal tri-cyclic antidepressants produce spinal anesthesia.

Abstract Tri‐cyclic antidepressants (TCAs) have been widely used in treating major depressive disorders. Recent studies further demonstrated that TCAs have potent sodium channel blocking effect, and amitriptyline, one of the TCAs, has a potent spinal anesthetic effect. The aim of the study was to evaluate the spinal anesthetic effect of various TCAs and to see whether these TCAs could likewise act as local anesthetics after a single intrathecal injection. Bupivacaine, a potent and long‐acting traditional local anesthetic, acted as control. The spinal anesthetic effect of nine TCAs (amitriptyline, doxepin, imipramine, trimipramine, clomipramine, protriptyline, desipramine, nortriptyline, and amoxapine) and three traditional local anesthetics (bupivacaine, lidocaine, and mepivacaine) was evaluated in rats and so were dose–response studies of amitriptyline, bupivacaine, and lidocaine. Under a given concentration of 5 mM, bupivacaine had the most potent spinal blockade of motor, propioception, and nociception (P<0.001) and the longest duration of action of nociception (P<0.01) among the three traditional local anesthetics. Under this concentration, amitriptyline had a similar potency but longer duration of spinal blockade of motor, propioception, and nociception (P<0.001) than did bupivacaine, whereas several other TCAs had similar or less potencies of spinal blockade than did bupivacaine. In dose–response studies, amitriptyline had a more potent (P<0.005) and longer duration (P<0.001) of spinal blockade than did bupivacaine. We concluded that intrathecal amitriptyline had a more potent and longer duration of spinal anesthetic effect than did bupivacaine, whereas several other TCAs had similar or less potencies than did bupivacaine.

Resuscitation from experimental heatstroke by transplantation of human umbilical cord blood cells.

Objective:Human umbilical cord blood cells (HUCBCs) are effective in the treatment of conventional stroke in experimental models. In the study described herein, we administered HUCBCs into the femoral vein or directly into the cerebral ventricular system and assessed their effects on circulatory shock, cerebral ischemia, and damage during heatstroke. Design:Controlled, prospective study. Setting:Hospital medical research laboratory. Subjects:Sprague-Dawley rats (287 ± 16 g body weight, males). Interventions:Anesthetized rats, immediately after the onset of heatstroke, were divided into four major groups and given the following: a) normal saline or AIM-V medium intravenously (0.3 mL) or intracerebroventricularly (10 &mgr;L); b) peripheral blood mononuclear cells (5 × 106 in 0.3 mL AIM-V medium, intravenously, or 5 × 105 in 10 &mgr;L AIM-V medium, intracerebroventricularly); or c) HUCBCs (5 × 106 in 0.3 mL AIM-V medium, intravenously, or 5 × 105 in 10 &mgr;L AIM-V medium, intracerebroventricularly). Another group of rats, under urethane anesthesia, were exposed to room temperature (26°C) and used as normothermic controls. Urethane-anesthetized animals were exposed to an ambient temperature of 43°C to induce heatstroke. Their physiologic and biochemical parameters were continuously monitored. Measurements and Main Results:When the vehicle-treated rats underwent heat exposure, their survival time values were found to be 21–23 mins. Resuscitation with intravenous or intracerebroventricular doses of HUCBCs, but not peripheral blood mononuclear cells, immediately at the onset of heatstroke significantly improved survival during heatstroke (61–148 mins). As compared with values for normothermic controls, the vehicle-treated heatstroke rats had lower mean arterial pressure, cerebral blood flow, and brain Po2 values but higher intracranial pressure and cerebral ischemia values and more injury markers. The circulatory shock, intracranial hypertension, cerebral hypoperfusion and hypoxia, increment of cerebral ischemia, and damage markers during heatstroke were all significantly attenuated by intravenous or intracerebroventricular delivery of HUCBCs but not peripheral blood mononuclear cells. Conclusions:We successfully demonstrate that HUCBC therapy may resuscitate heatstroke victims by reducing circulatory shock and cerebral ischemic injury; central delivery of HUCBCs seems superior to systemic delivery of HUCBCs in resuscitating patients with heatstroke.

Inhibition of nuclear factor-kappa B prevents staphylococcal enterotoxin A-induced fever

It has been shown that staphylococcal enterotoxin A (SEA) acts through human peripheral blood mononuclear cells (PBMC) to stimulate synthesis or release of pyrogenic cytokines. Nuclear factor-kappa B (NF-κB) is thought to play an important role in inflammatory responses through the regulation of genes encoding pro-inflammatory cytokines. The purpose of the present study was to determine whether the NF-κB mechanisms in human PBMC are involved in SEA-induced fever. Western blot evaluation revealed SEA was able to induce nuclear translocation of NF-κB from cytosol to nucleus in PBMC, which could be abolished by a NF-κB inhibitor such as pyrrolidine dithiocarbamate (PDTC), sodium pyrithione (Pyri), N-acetyl-L-cysteine (NAC), or curcumin (Cur). Electrophoretic mobility shift assay also showed that the NF-κB DNA-binding activity was increased in the SEA-treated PBMC. Again, the SEA-induced increased NF-κB binding activity was significantly attenuated by either PDTC, Pyri, NAC or Cur. The pyrogenic responses to supernatant fluids obtained from human PBMC stimulated with SEA were associated with increased levels of interleukin 1-β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) in the supernatant fluids. Both the fever and the increased levels of IL-1β, IL-6, and TNF-α in supernatant fluids obtained from the SEA-stimulated PBMC were decreased by incubating SEA-PBMC with either PDTC, Pyri, NAC, or Cur. Furthermore, the fever induced by systemic or central administration of SEA in rabbits were attenuated by pre-treatment with an systemic or central dose of either PDTC, Pyri, NAC, or Cur. The data indicate that inhibition of NF-κB prevents SEA-induced fever. (Mol Cell Biochem 262: 177–185, 2004)

Brain Cooling-Stimulated Angiogenesis and Neurogenesis Attenuated Traumatic Brain Injury in Rats

BACKGROUND Although brain cooling has been reported to be effective in improving the outcome after traumatic brain injury (TBI) in rats, the mechanisms of brain cooling-induced neuroprotective actions remain unclear. This study was to test whether angiogenesis and neurogenesis attenuating TBI could be brain cooling stimulated. METHODS Anesthetized rats, immediately after the onset of TBI, were divided into two groups and given the brain cooling (infusing 5 mL of 4°C saline via the external jugular vein) or no brain cooling (infusing 5 mL of 37°C saline via the external jugular vein). RESULTS Brain cooling without interference with the core temperature in rats significantly attenuated TBI-induced cerebral infarction (90 mm³ vs. 250 mm³) and motor (61 degrees vs. 57 degrees maximal angle) and proprioceptive (14% vs. 42% maximal possible effect) function deficits, significantly reduced TBI-induced neuronal (24 vs. 62 neuronal-specific nuclear [NeuN]-TUNEL double-positive cells) and glial (5 vs. 35 GFAP-TUNEL double-positive cells) apoptosis (increased TUNEL-positive and caspase-3-positive cells), neuronal loss (102 vs. 66 NeuN-positive cells), and gliosis (40 vs. 66 GFAP-positive cells; 66 vs. 89 Iba1-positive cells), and significantly promoted angiogenesis (5-bromodeoxyuridine [BrdU]/endothelial cells vs. 1-BrdU/endothelial cell; 58 vs. 31 vascular endothelial growth factor-positive cells), and neurogenesis (33 vs. 14 BrdU/NeuN positive cells). CONCLUSIONS Brain cooling-stimulated angiogenesis and neurogenesis attenuated a fluid percussion TBI in rats.

The antipyretic effects of baicalin in lipopolysaccharide-evoked fever in rabbits

Evidence has accumulated to indicate that systemic administration of lipopolysaccharide (LPS), in addition to elevating tumor necrosis factor-alpha (TNF-alpha) as well as fever, induces overproduction of both glutamate and hydroxyl radicals in the rabbits hypothalamus. Current investigation was attempted to determine whether baicalin exerts its antipyresis by suppressing overproduction of circulating TNF-alpha and hypothalamic glutamate and hydroxyl radicals in rabbits. The microdialysis probes were stereotaxically and chronically implanted into the preoptic anterior hypothalamus of rabbit brain for determination of both glutamate and hydroxyl radicals in situ. It was found that systemic administration of LPS (0.5-10 microg/kg) induced dose-related increased levels of both core temperature and hypothalamic levels of both glutamate and hydroxyl radicals accompanied by increased plasma levels of TNF-alpha. The rise in both the core temperature and hypothalamic glutamate and hydroxyl radicals could also be induced by direct injection of TNF-alpha (1-20 ng) into the lateral ventricle of rabbit brain. Pretreatment with baicalin (2-20 mg/kg, i.v.) one hour before an i.v. dose of LPS significantly reduced the LPS-induced overproduction of circulating TNF-alpha and brain glutamate and hydroxyl radicals. Both the febrile response and overproduction of both glutamate and hydroxyl radicals in the hypothalamus caused by central administration of TNF-alpha could be suppressed by baicalin. These findings suggest that systemic administration of baicalin may exert its antipyresis by inhibiting the N-methyl-D-aspartate receptor-dependent hydroxyl radicals pathways in the hypothalamus and circulating TNF-alpha accumulation during LPS-fever.