The effects of selective brain hypothermia and decompressive craniectomy on brain edema after closed head injury in mice.

Intractable brain edema remains one of the main causes of death after traumatic brain injury (TBI). Brain hypothermia and decompressive craniectomy have been considered as potential therapies. The goal of our experimental study was to determine if selective hypothermia in combination with craniectomy could modify the development of posttraumatic brain edema. Male CD-1 mice were anesthetized with halothane and randomly assigned into the following groups: sham-operated (n = 5), closed head injury (CHI) alone (n = 5), CHI followed by craniectomy at 1 h post-TBI (n = 5) and CHI + craniectomy and selective hypothermia (focal brain cooling using cryosurgery device) maintained for 5 h (n = 5). Animals were sacrificed at 7 h posttrauma and brains were removed, sagittally dissected and dried. The brain water content of separate hemispheres was calculated from the weight difference before and after drying. In the CHI alone group there was no significant increase in brain water content in both the ipsi- and contralateral hemispheres (80.59 +/- 1% and 78.74 +/- 0.9% in the CHI group vs. 79.31 +/- 0.7% and 79.01 +/- 0.3% in the sham group, respectively). Brain edema was significantly increased ipsilaterally in the trauma + craniectomy group (82.11 +/- 0.6%, p < 0.05), but not in the trauma + craniectomy + hypothermia group (81.52 +/- 1.1%, p > 0.05) as compared to the sham group (79.31 +/- 0.7%). These data suggest that decompressive craniectomy leads to an increase in brain water content after CHI. Additional focal hypothermia may be an effective approach in the treatment of posttraumatic brain edema.

Brain Edema Formation and Functional Outcome After Surgical Decompression in Murine Closed Head Injury Are Modulated by Acetazolamide Administration.

Acetazolamide (ACZ), carbonic anhydrase inhibitor, has been successfully applied in several neurosurgical conditions for diagnostic or therapeutic purposes. Furthermore, neuroprotective and anti-edematous properties of ACZ have been postulated. However, its use in traumatic brain injury (TBI) is limited, since ACZ-caused vasodilatation according to the Monro-Kellie doctrine may lead to increased intracranial blood volume / raise of intracranial pressure. We hypothesized that these negative effects of ACZ will be reduced or prevented, if the drug is administered after already performed decompression. To test this hypothesis, we used a mouse model of closed head injury (CHI) and decompressive craniectomy (DC). Mice were assigned into following experimental groups: sham, DC, CHI, CHI+ACZ, CHI+DC, and CHI+DC+ACZ (n = 8 each group). 1d and 3d post injury, the neurological function was assessed according to Neurological Severity Score (NSS) and Beam Balance Score (BBS). At the same time points, brain edema was quantified by MRI investigations. Functional impairment and edema volume were compared between groups and over time. Among the animals without skull decompression, the group additionally treated with acetazolamide demonstrated the most severe functional impairment. This pattern was reversed among the mice with decompressive craniectomy: CHI+DC treated but not CHI+DC+ACZ treated animals showed a significant neurological deficit. Accordingly, radiological assessment revealed most severe edema formation in the CHI+DC group while in CHI+DC+ACZ animals, volume of brain edema did not differ from DC-only animals. In our CHI model, the response to acetazolamide treatment varies between animals with decompressive craniectomy and those without surgical treatment. Opening the cranial vault potentially creates an opportunity for acetazolamide to exert its beneficial effects while vasodilatation-related risks are attenuated. Therefore, we recommend further exploration of this potentially beneficial drug in translational research projects.

Changes in Posttraumatic Brain Edema in Craniectomy-Selective Brain Hypothermia Model Are Associated With Modulation of Aquaporin-4 Level.

Both hypothermia and decompressive craniectomy have been considered as a treatment for traumatic brain injury. In previous experiments we established a murine model of decompressive craniectomy and we presented attenuated edema formation due to focal brain cooling. Since edema development is regulated via function of water channel proteins, our hypothesis was that the effects of decompressive craniectomy and of hypothermia are associated with a change in aquaporin-4 (AQP4) concentration. Male CD-1 mice were assigned into following groups (n = 5): sham, decompressive craniectomy, trauma, trauma followed by decompressive craniectomy and trauma + decompressive craniectomy followed by focal hypothermia. After 24 h, magnetic resonance imaging with volumetric evaluation of edema and contusion were performed, followed by ELISA analysis of AQP4 concentration in brain homogenates. Additional histopathological analysis of AQP4 immunoreactivity has been performed at more remote time point of 28d. Correlation analysis revealed a relationship between AQP4 level and both volume of edema (r 2 = 0.45, p < 0.01, **) and contusion (r 2 = 0.41, p < 0.01, **) 24 h after injury. Aggregated analysis of AQP4 level (mean ± SEM) presented increased AQP4 concentration in animals subjected to trauma and decompressive craniectomy (52.1 ± 5.2 pg/mL, p = 0.01; *), but not to trauma, decompressive craniectomy and hypothermia (45.3 ± 3.6 pg/mL, p > 0.05; ns) as compared with animals subjected to decompressive craniectomy only (32.8 ± 2.4 pg/mL). However, semiquantitative histopathological analysis at remote time point revealed no significant difference in AQP4 immunoreactivity across the experimental groups. This suggests that AQP4 is involved in early stages of brain edema formation after surgical decompression. The protective effect of selective brain cooling may be related to change in AQP4 response after decompressive craniectomy. The therapeutic potential of this interaction should be further explored.

Changes in cortical and subcortical energy metabolism after repetitive and single controlled cortical impact injury in the mouse.

In the present investigation we examined regional ATP, glucose, and lactate content in the cortical and subcortical region, in a mouse model of controlled cortcal impact (CCI) injury. In serial tissue sections, bioluminescence imaging of ATP, glucose, and lactate was performed 1 h after a single CCI injury or sham surgery and 15 min, 1, 24, and 48 h after the induction of a second CCI injury 24 h later or sham surgery. Bioluminescence images were analyzed by computer-assisted densitometry at the lesion site, at the contralateral site, and in a subcortical region. After repetitive CCI injury, the cortical ATP content decreased bilaterally at 15 min and 1 h, and reached a significant minimum at 24 h, as compared with sham. At 48 h the ATP content bilaterally reached base level again. No significant changes in ATP were found in the subcortical region. After repetitive CCI injury, the lactate content increased bilaterally, reached a significant level at 15 min at the trauma site, and bilaterally reached a significant maximum at 1 h. Thereafter, lactate content decreased below base level without reaching significance and reached baseline again at 48 h. In the ipsilateral subcortical region, lactate content increased transiently above the baseline at 1 h and decreased to a significant minimum at 24 and 48 h. No significant changes were found in the contralateral subcortical area. No significant differences between glucose content in sham animals and the cortical and subcortical area could be measured over time; the subcortical glucose content was bilaterally lower than cortical content at all time points and reached a significant minimum bilaterally at 48 h after repetitive CCI injury compared with cortical glucose content. Single CCI injury did not affect ATP, glucose, and lactate contents at any time point. Repetitive CCI injury caused a more severe depression in cerebral metabolism at early time points after trauma compared with a single CCI injury and indicates that lactate might be an early indicator of post-traumatic metabolic disruption.

Closed head injury causes hyperexcitability in rat hippocampal CA1 but not in CA3 pyramidal cells.

Traumatic brain injury frequently elicits epileptic seizures hours or days after the impact. The mechanisms on cellular level are poorly understood. Because posttraumatic epilepsy appears in many cases as a temporal-lobe epilepsy which originated the hippocampus, we studied trauma-induced hyperexcitability on the cellular level in this brain area. We used the model of closed head injury to analyse the electrophysiological changes in CA1 and CA3 pyramidal cells and in interneurones of the CA1 field, which is extremely sensitive to ischemia. We found that morphologically closed head injury (CHI) led to a gradual progressive, cell type specific time course in neuronal degeneration. To analyse electrophysiological impairment we measured resting membrane potential, recorded spontaneous action potentials and induced action potentials by current pulses at different times after CHI. We found a dramatic increase in the frequency of spontaneous action potentials of CA1 but not of CA3 pyramidal cells after CHI. This hyperexcitability was maximal at 2 h (4.5-fold higher than sham), was also observed at 24 h after CHI and disappeared after 3 days. We found that CA1 interneurones responded by a much weaker increase of AP frequency after CHI. We conclude that the strong hyperexcitability after CHI is cell-type specific and transient. The understanding of the complex neuronal interactions probably offers a promising possibility for pharmacological intervention to prevent posttraumatic epilepsy.

Heterogeneous regional and temporal energetic impairment following controlled cortical impact injury in rats.

OBJECTIVES: Following traumatic brain injury metabolic stability is impaired. Duration and reversibility of these changes might be important to guide specific interventions. METHODS: To characterize temporal and regional changes in cerebral metabolism, 68 male Sprague-Dawley rats were subjected to a focal cortical contusion. Lesion progression and mitochondrial impairment were determined by magnetic resonance imaging (MRI) and triphenyl tetrazolium chloride (TTC) staining, respectively. Metabolic alterations were determined at hours 6 and 24 and day 7 by measuring extracellular glucose, lactate and hypoxanthine levels with microdialysis catheters placed adjacent and distant to the contusion and by quantifying changes in tissue ATP, lactate and glucose using bioluminescence imaging. RESULTS: The cortical lesion reached its maximal extent at hour 24 and remained confined to the ipsilateral hemisphere. In microdialysate, at hour 6, extracellular hypoxanthine and lactate reached maximal values, thereafter hypoxanthine normalized while lactate remained increased. Extracellular glucose reached the highest values at hour 24 and remained elevated. Bioluminescence imaging revealed heterogeneous changes in areas distant to the contusion. No significant changes were found in ATP content. Slightly elevated tissue glucose until 24 hours in the ipsilateral hemisphere was observed. Following a continuous increase, lactate levels were the highest by 6 hours in the ipsilateral cortex and hippocampus. DISCUSSION: CCI is associated with disturbances in energetic metabolism. Metabolic perturbation is not restricted to the early phase and the contusional region following focal cortical contusion, but also involves hippocampus and primarily uninjured parts of the hemisphere.

Selective Brain Hypothermia Mitigates Brain Damage and Improves Neurological Outcome after Post-Traumatic Decompressive Craniectomy in Mice.

Hypothermia and decompressive craniectomy (DC) have been considered as treatment for traumatic brain injury. The present study investigates whether selective brain hypothermia added to craniectomy could improve neurological outcome after brain trauma. Male CD-1 mice were assigned into the following groups: sham; DC; closed head injury (CHI); CHI followed by craniectomy (CHI+DC); and CHI+DC followed by focal hypothermia (CHI+DC+H). At 24 h post-trauma, animals were subjected to Neurological Severity Score (NSS) test and Beam Balance Score test. At the same time point, magnetic resonance imaging using a 9.4 Tesla scanner and subsequent volumetric evaluation of edema and contusion were performed. Thereafter, the animals were sacrificed and subjected to histopathological analysis. According to NSS, there was a significant impairment among all the groups subjected to trauma. Animals with both trauma and craniectomy performed significantly worse than animals with craniectomy alone. This deleterious effect disappeared when additional hypothermia was applied. BBS was significantly worse in the CHI and CHI+DC groups, but not in the CHI+DC+H group, compared to the sham animals. Edema and contusion volumes were significantly increased in CHI+DC animals, but not in the CHI+DC+H group, compared to the DC group. Histopathological analysis showed that neuronal loss and contusional blossoming could be attenuated by application of selective brain hypothermia. Selective brain cooling applied post-trauma and craniectomy improved neurological function and reduced structural damage and may be therefore an alternative to complication-burdened systemic hypothermia. Clinical studies are recommended in order to explore the potential of this treatment.

Decompressive Craniectomy Increases Brain Lesion Volume and Exacerbates Functional Impairment in Closed Head Injury in Mice.

Decompressive craniectomy has been widely used in patients with head trauma. The randomized clinical trial on an early decompression (DECRA) demonstrated that craniectomy did not improve the neurological outcome, in contrast to previous animal experiments. The goal of our study was to analyze the effect of decompressive craniectomy in a murine model of head injury. Male mice were assigned into the following groups: sham, decompressive craniectomy, closed head injury (CHI), and CHI followed by craniectomy. At 24 h post-trauma, animals underwent the Neurological Severity Score test (NSS) and Beam Balance Score test (BBS). At the same time point, magnetic resonance imaging was performed, and volume of edema and contusion was assessed, followed by histopathological analysis. According to NSS, animals undergoing both trauma and craniectomy presented the most severe neurological impairment. Also, balancing time was reduced in this group compared with sham animals. Both edema and contusion volume were increased in the trauma and craniectomy group compared with sham animals. Histopathological analysis showed that all animals that underwent trauma presented substantial neuronal loss. In animals treated with craniectomy after trauma, a massive increase of edema with hemorrhagic transformation of contusion was documented. Decompressive craniectomy applied after closed head injury in mice leads to additional structural and functional impairment. The surgical decompression via craniectomy promotes brain edema formation and contusional blossoming in our model. This additive effect of combined mechanical and surgical trauma may explain the results of the DECRA trial and should be explored further in experiments.

Characterization of a new rat model of experimental combined neurotrauma.

Traumatic brain injury (TBI) is present in two-thirds of patients with multiple injuries and in one-third combined with injuries of the extremities. Studies on interactive effects between central and peripheral injuries are scarce due to the absence of clinically relevant models. To meet the demand for "more-hit" models, an experimental model of combined neurotrauma (CNT) incorporating a standardized TBI via lateral fluid percussion (LFP) together with a peripheral bone fracture, i.e., tibia fracture, is introduced. Sprague-Dawley rats were randomized to four experimental groups: controls (n = 10), animals with TBI (n = 30), animals with tibia fracture (n = 30), and animals with CNT (n = 30). Morphological aspects of brain and bone injury were analyzed via standard histopathological procedures and x-ray. Trauma-induced neuromotor dysfunction was assessed using a standardized neuroscore. For interactive effects between injuries, we studied the extent and temporal pattern of circulating interleukin 6 (IL-6) levels via immunoassay and callus formation at fracture sites by means of microradiography. LFP produced an ipsilateral lesion with cortical contusion, hemorrhage, mass shift, and neuronal cell loss (adjacent cortex and hippocampus CA-2/-3), along with contralateral neuromotor dysfunction. X-rays confirmed complete fractures in the middle of the bone shaft. The type of injury (P < 0.001) and time (P = 0.022) were significantly associated with increased IL-6 levels. CNT produced the highest IL-6 plasma levels with a maximum peak at 6 h after trauma (P < 0.001). Similarly, callus formation at fracture sites in CNT was significantly increased versus fracture only (P < 0,01). The CNT model mimics a variety of clinically relevant features known from human multiple injury, including TBI, and offers novel approaches for investigation of interactive mechanisms and therapeutic approaches.

Spinal cord trauma activates processing of xbp1 mRNA indicative of endoplasmic reticulum dysfunction.

The contribution of the various subcellular compartments in the induction of cell injury triggered by spinal cord trauma has not been clearly elucidated yet. In the present study, we investigated changes in mRNA levels of processed xbp1, ho-1, and hsp70 induced in mice by hemisection or contusion of the spinal cord. The expression of these genes is upregulated under conditions associated with endoplasmic reticulum (ER; xbp1, ho-1) dysfunction or impairment of cytoplasmic function (hsp70) respectively. When the functioning of the ER or the cytoplasm is impaired, unfolded proteins accumulate in these compartments. This is the warning signal for activation of the unfolded protein response (ER) and heat-shock response (cytoplasm) respectively. Spinal cord trauma activated the expression of these genes starting at 3 h and peaking at 6 h of recovery (processed xbp1, 12-fold and fivefold increase; ho-1, fourfold and eightfold increase; hsp70, fourfold, no increase, after contusion and hemisection, respectively). After 6 h of recovery, the rise in hsp70 mRNA levels was confined to the traumatized segment (fourfold), whereas a significant increase in processed xbp1 and ho-1 mRNA levels was also observed in the adjacent segments. This suggests a spread of the pathological process from the site of the primary impact into the surrounding tissue. After induction of spinal cord trauma processed xbp1 mRNA levels rose in a delayed fashion. This implies that the pathological process that causes impairment of ER functioning, starts with a delay of a few hours after induction of trauma and may therefore be amenable to therapeutic intervention.

Recovery of hepatocellular ATP and "pericentral apoptosis" after hemorrhage and resuscitation.

Progressive liver dysfunction contributes significantly to the development of multiple organ failure after trauma/hemorrhage. This study tested the relative impact of necrotic and apoptotic cell death in a graded model of hemorrhagic shock (mean arterial blood pressure=35+/-5 mmHg for 1, 2, or 3 h, followed by 2 h, 1 h, or no resuscitation, respectively) in rats. Prolonged periods of hemorrhagic hypotension (3 h) were paralleled by a profound decrease of hepatic ATP levels and occurrence of pericentral necrosis. Resuscitation after shorter periods of hemorrhagic hypotension resulted in restoration of tissue ATP whereas hepatocellular function as assessed by indocyanine green clearance remained depressed (49.9+/-1.6 mL/(min x kg) at baseline, 28.8+/-1.2 mL/(min x kg) after 2 h of resuscitation; P<0.05). Under these conditions, induction of caspase activity and DNA fragmentation were observed in pericentral hepatocytes that could be prevented by the radical scavenger tempol. Pretreatment with z-Val-Ala-Asp(O-methyl)-flouromethylketone prevented de novo expression of caspase-generated cytokeratin 18, DNA fragmentation, and depression of hepatocellular indocyanine green clearance. These data suggest that prolonged low flow/hypoxia induces ATP depletion and pericentral necrosis and restoration of oxygen supply and ATP levels after shorter periods of low flow ischemia propagate programmed cell death or "pericentral apoptosis."

Multimodal MR imaging of acute and subacute experimental traumatic brain injury: Time course and correlation with cerebral energy metabolites.

BACKGROUND: Traumatic brain injury (TBI) is one of the leading causes of death and permanent disability world-wide. The predominant cause of death after TBI is brain edema which can be quantified by non-invasive diffusion-weighted magnetic resonance imaging (DWI). PURPOSE: To provide a better understanding of the early onset, time course, spatial development, and type of brain edema after TBI and to correlate MRI data and the cerebral energy state reflected by the metabolite adenosine triphosphate (ATP). MATERIAL AND METHODS: The spontaneous development of lateral fluid percussion-induced TBI was investigated in the acute (6 h), subacute (48 h), and chronic (7 days) phase in rats by MRI of quantitative T2 and apparent diffusion coefficient (ADC) mapping as well as perfusion was combined with ATP-specific bioluminescence imaging and histology. RESULTS: An induced TBI led to moderate to mild brain damages, reflected by transient, pronounced development of vasogenic edema and perfusion reduction. Heterogeneous ADC patterns indicated a parallel, but mixed expression of vasogenic and cytotoxic edema. Cortical ATP levels were reduced in the acute and subacute phase by 13% and 27%, respectively, but were completely normalized at 7 days after injury. CONCLUSION: The partial ATP reduction was interpreted to be partially caused by a loss of neurons in parallel with transient dilution of the regional ATP concentration by pronounced vasogenic edema. The normalization of energy metabolism after 7 days was likely due to infiltrating glia and not to recovery. The MRI combined with metabolite measurement further improves the understanding and evaluation of brain damages after TBI.

Regional energy metabolism following short-term neural stem cell transplantation into the injured spinal cord.

Stem cells have been shown to partly restore central nervous system (CNS) function after transplantation into the injured CNS. However, little is known about their influence on acute energy metabolism after spinal cord injury. The present study was designed to analyze regional changes in energy metabolites. Young adult mice were subjected to laminectomy with subsequent hemisection at the L2/3 vertebral level. Immediately thereafter a stable clone of murine neural stem cells (NSCs) was injected into the lesion site. After 4 and 24 h, spinal cords were removed and ATP, glucose, and lactate were analyzed by a bioluminescence approach in serial sections and compared to a laminectomized (intact control), hemisected-only or hemisected vehicle-injected control group. At both time points, ATP content of the hemisected group in the tissue segments adjacent to the lesion was increased when compared to the laminectomized control. At the lesion site ATP content decreased significantly at 24 h in the cell-transplanted group when compared to the laminectomized control group. Glucose content decreased at the lesion site and in segments adjacent to the lesion at both time points and in all experimental groups when compared to the laminectomized control group. Lactate content decreased significantly at 4 h in the caudal segments of the vehicle-injected group and in both adjacent segments of the transplanted group when compared to the laminectomized control. At the lesion site, lactate content decreased significantly at 4 and 24 h in the cell-transplanted group, when compared to the laminectomized control. The area of ATP decline at the lesion site 24 h postinjury was significantly lower in the vehicle control group as compared to the hemisected or transplanted group. The decrease in glucose combined with an increase in ATP in the lesion-adjacent segments may indicate that the tissue responds with an increased use of glucose to support itself with sufficient ATP. The significant decrease in glucose, lactate, and ATP in the cell-transplanted group at 24 h may indicate a high metabolic need of the stem cells. The lower area of ATP decline 24 h after vehicle administration suggests that the vehicle solution washes out toxic mediators, thus ameliorating hemisection-dependent secondary tissue damage.

Changes in regional energy metabolism after cortical cold lesion in the rat brain.

In the present investigation, regional ATP, glucose, and lactate contents were examined in the cortical and subcortical structures after cold lesion in rats. Bioluminescence imaging of ATP, glucose, and lactate was performed in serial tissue sections at 4 h (n = 4), 12 h (n = 4) and 24 h (n = 4) after cold injury or sham surgery. Bioluminescence images were analyzed by computer-assisted densitometry, at the lesion site, in cortical areas, in the hippocampus, and in the thalamus. ATP and glucose content were significantly decreased at the lesion site as well as on the contralateral side after 4, 12, and 24 h postinjury Lactate content increased significantly in the hippocampal area on the ipsilateral side at 12 h. Cortical lactate was bilaterally unchanged. The cold lesion injury led to a characteristic ischemic profile in the hippocampus signaled by low ATP and glucose content paralleled by high lactate levels. The otherwise global depletion of glucose and ATP suggests that other factors besides cerebral blood flow may contribute to the impairment of energy metabolism.

Microvascular basal lamina antigen loss after traumatic brain injury in the rat.

The loss of microvascular basal lamina antigen is known to be a consequence of cerebral ischemia, but little information is available on its role in traumatic brain injury (TBI). The aim of our study was (1) to test the hypothesis that there is damage to the basal lamina of brain microvasculature after TBI, (2) to localize microvascular damage, and (3) to compare this loss with that in ischemia. Rats (n=14) were either sham operated (n=5) or subjected to fluid percussion injury (n=9; TBI=1.5 atm) and killed after 0 (n=5, sham), 12 (n=4), or 24 h (n=5). Collagen-type-IV immunoreactivity and a digital image-processing system were used to localize and quantify the number of stained vascular elements and the total collagen stained area. Western blot was used to compare collagen-type-IV content on the traumatic and nontraumatic brain side. The cortex of animals subjected to TBI and killed after 24 h showed a reduction in the area of stained collagen amounting to 19+/-4% (p<0.009) and a reduction in the total number of microvessels identified by collagen stain (29+/-6%; p<0.02). The Western blot revealed a 31+/-6% (p<0.03) reduction of collagen, compared to the mirror cortical area after 24 h. No significant reduction was found in the group that survived 12 h or in basal ganglia in both groups. TBI causes microvascular basal lamina damage. Whereas TBI affected only cortical areas, cerebral ischemia also induced microvascular basal lamina damage in the basal ganglia. After 24 h, the extent of severe basal lamina damage due to TBI was less severe than in ischemia.

Effects of immediate and delayed facial-facial nerve suture on rat facial muscle.

OBJECTIVE: To investigate regeneration of the mimic musculature after delayed facial nerve repair. MATERIALS AND METHOD: In 30 rats the facial nerve on the right side was resected and immediately repaired with an end-to-end anastomosis. The entire levator labii muscle was removed on the right side and histochemically and morphometrically analyzed at 7, 14, 21, 28, 90 and 180 days after immediate nerve repair. In a further 20 rats, reinnervation was performed after 4 weeks in a further operation and the muscle was assessed at 14, 28, 90 and 180 days. Seven muscles of four normal rats were used as controls. RESULTS: Three muscle fiber types could be identified by comparative histochemical analysis of two enzymes of succinate dehydrogenase (SDH) and m-ATPase: oxidative glycolytic (FOG) fibers, fast glycolytic (FG) fibers and intermediate muscle fibers that were designated SDH-INT. The number of fibers and the frequency distribution of single-fiber cross-sectional areas were determined for each type of fiber. No significant difference in the cross-sectional area of all fiber types was noted after 180 days when comparing immediate and delayed end-to-end sutures. In contrast, comparison of the fiber-type composition showed a significant increase in the number of FG fibers in the delayed suture, at the expense of FOG fibers. After immediate reinnervation the muscle approximately attained its natural fiber-type composition, whereas after delayed reinnervation the muscle showed an overall loss of oxidative capacity and differentiation towards phasic activity. CONCLUSION: Changes in fiber-type composition following delayed nerve suture are irreversible and have specific effects on the precise function of the muscle. Immediate nerve repair improves axonal reinnervation.

Stress-resistant neural stem cells positively influence regional energy metabolism after spinal cord injury in mice.

The importance of stem cells to ameliorate the devastating consequences of traumatic injuries in the adult mammalian central nervous system calls for improvements in the capacity of these cells to cope, in particular, with the host response to the injury. We have previously shown, however, that in the acutely traumatized spinal cord local energy metabolism led to decreased ATP levels after neural stem cell (NSC) transplantation. As this might counteract NSC-mediated regenerative processes, we investigated if NSC selected for increased oxidative stress resistance are better suited to preserve local energy content. For this purpose, we exposed wild-type (WT) NSC to hydrogen peroxide prior to transplantation. We demonstrate here that transplantation of WT-NSC into a complete spinal cord compression injury model even lowers the ATP content beyond the level detected in spinal cord injury-control animals. Compared to WT-NSC, stress-resistant (SR) NSC did not lead to a further decrease in ATP content. These differences between WT- and SR-NSC were observed 4 h after the lesion with subsequent transplantation. At 24 h after lesioning, these differences were no more as obvious. Thus, in contrast to native NSC, transplantation of NSC selected for oxidative stress resistance can positively influence local energy metabolism in the first hours after spinal cord compression. The functional relevance of this observation has to be tested in further experiments.

Efficacy of systemic radionuclide therapy with p-131I-iodo-L-phenylalanine combined with external beam photon irradiation in treating malignant gliomas.

UNLABELLED: p-(131)I-iodo-L-phenylalanine ((131)I-IPA) is a tumor-specific amino acid derivative that demonstrated antiproliferative and tumoricidal effects on experimental gliomas. This study tested the efficacy of (131)I-IPA combined with external beam photon radiotherapy as a new therapeutic approach against gliomas. METHODS: Glioma cells derived from the rat F98 glioma or human Tx3868 or A1207 glioblastoma cell lines were stereotactically inoculated into the brains of Fischer 344 rats or RNU rats. Tumor formation was verified radiologically. On day 8, groups of glioma-bearing rats of each tumor model underwent whole-brain radiotherapy with 8 Gy, an intravenous administration of (131)I-IPA (30 MBq), or combined treatment, aiming for a total of 12 rats per group. Another 12 animals were treated with physiologic saline and served as control. RESULTS: Control rats had a combined median survival (+/-SD) of 21 +/- 6 d. All revealed metabolically and histologically large tumor masses. Efficacy of radiotherapy alone or a monotherapy with 30 MBq of (131)I-IPA was statistically insignificant on the syngeneic Fischer-F98 model (P >or= 0.45 and P = 0.10, respectively). In contrast, a subset of long-term survivors (>120 d) was observed in RNU rats bearing Tx3868 and A1207 glioblastoma xenografts (18%-25% and 35%-45% for radiotherapy and (131)I-IPA, respectively). Combined (131)I-IPA and radiotherapy treatment significantly prolonged median survival for the syngeneic Fischer-F98 glioma model (P < 0.01) and human glioblastoma-bearing RNU rats alike (P < 0.05). On day 120 after monotherapy with (131)I-IPA, 45% of the RNU rats were still alive, but after 8 Gy of photon radiotherapy only 18%-25% of the RNU and none of the Fischer rats survived. In comparison, 55%-75% survival rates were registered after combined treatment on day 120 for all animal models. CONCLUSION: These data convincingly demonstrated that systemic radionuclide therapy with (131)I-IPA combined with external photon radiotherapy is a safe and highly effective treatment for experimental gliomas, which may merit a clinical trial to ascertain its potential in patients with gliomas. Because only a low (131)I-IPA activity and low radiotherapy doses were applied, further optimizations including higher radiation doses and conventional fractionated radiotherapy are warranted.