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Annually, there are over 2 million incidents of traumatic brain injury (TBI) and treatment options are non-existent. While many TBI studies have focused on the brain, peripheral contributions involving the digestive and immune systems are emerging as factors involved in the various symptomology associated with TBI. We hypothesized that TBI would alter hepatic function, including bile acid system machinery in the liver and brain. The results show activation of the hepatic acute phase response by 2 hours after TBI, hepatic inflammation by 6 hours after TBI and a decrease in hepatic transcription factors, Gli 1, Gli 2, Gli 3 at 2 and 24 hrs after TBI. Bile acid receptors and transporters were decreased as early as 2 hrs after TBI until at least 24 hrs after TBI. Quantification of bile acid transporter, ASBT-expressing neurons in the hypothalamus, revealed a significant decrease following TBI. These results are the first to show such changes following a TBI, and are compatible with previous studies of the bile acid system in stroke models. The data support the emerging idea of a systemic influence to neurological disorders and point to the need for future studies to better define specific mechanisms of action.

Bone marrow-derived stromal cells (BMSCs) are defined by their ability to self-renew and differentiate into at least three mesenchymal cell types (bone, adipose, and cartilage). The inability to isolate a reliably efficacious and homogeneous population of early progenitor cells has limited efforts to increase their therapeutic potential. In this study, we focused on identifying protein markers that may be employed to predict the efficacy of a cultured BMSC population. Markers of progenitor status were identified by comparing BMSCs at early and late passage, donor-matched skin fibroblasts, and commercially available dermal fibroblast cell lines. Differentiation potential was determined according to in vitro assays of osteogenesis, adipogenesis, and chondrogenesis. Early-passage BMSCs differentiated into all three lineages, whereas late-passage BMSCs and both fibroblast preparations did not. To identify novel markers of early progenitors, microarray transcript analysis between early-passage BMSCs and fibroblasts was performed. Messenger RNA encoding the cytokine leukemia inhibitory factor (LIF) was identified as differentially expressed. Enzyme-linked immunosorbent assay on conditioned media confirmed that LIF secretion was much higher from early progenitor BMSCs than donor-matched or commercial lines of fibroblasts and dropped with extensive expansion or induction of differentiation. In clonally expanded BMSCs, colonies that retained progenitor status expressed significantly higher levels of LIF than those that failed to differentiate. Our results indicate that LIF expression may represent a marker to quantify the differentiation potential of BMSCs and may be especially suited for the rapid, noninvasive quality control of clinical preparations.

Multipotential bone marrow stromal cells (MSCs) from wild-type (Wt) or apolipoprotein E deficient ( Apoe − / − ) mice were implanted into the cerebral ventricles of Apoe − / − mice. MSCs from Wt mice continued expressing apoE up to 6 months after implantation and were associated with enhanced novel object recognition and increased microtubule-associated protein 2 (MAP2) immunoreactivity in the dentate gyrus. These data show that MSCs can be used to distinguish developmental from post-developmental effects of a gene knockout and support their therapeutic potential for neurodegenerative diseases.

Traumatic brain injury (TBI) has been reported to increase seizure susceptibility and also contribute to the development of epilepsy. However, the mechanistic basis of the development of increased seizure susceptibility and epilepsy is not clear. Though there is substantial work done using rats, data are lacking regarding the use of mice in the fluid percussion injury (FPI) model. It is unclear if mice, like rats, will experience increased seizure susceptibility following FPI. The availability of a mouse model of increased seizure susceptibility after FPI would provide a basis for the use of genetically modified mice to study mechanism(s) of the development of post-traumatic epilepsy. Therefore, this study was designed to test the hypothesis that, mice subjected to a FPI develop increased seizure susceptibility to a subconvulsive dose of the chemoconvulsant, pentylenetetrazole (PTZ). Three groups of mice were used: FPI, sham and naïve controls. On day thirty after FPI, mice from the three groups were injected with PTZ. The results showed that FPI mice exhibited an increased severity, frequency and duration of seizures in response to PTZ injection compared with the sham and naïve control groups. Histopathological assessment was used to characterize the injury at one, three, seven and thirty days after FPI. The results show that mice subjected to the FPI had a pronounced lesion and glial response that was centered at the FPI focus and peaked at three days. By thirty days, only minimal evidence of a lesion is observed, although there is evidence of a chronic glial response. These data are the first to demonstrate an early increase in seizure susceptibility following fluid percussion injury in mice. Therefore, future studies can incorporate transgenic mice into this model to further elucidate mechanisms of TBI-induced increases in seizure susceptibility.

The methodology for the repair of critical-sized or non-union bone lesions has unpredictable efficacy due in part to our incomplete knowledge of bone repair and the biocompatibility of bone substitutes. Although human mesenchymal stem cells (hMSCs) differentiate into osteoblasts, which promote bone growth, their ability to repair bone in vivo has been variable. We hypothesized that given the multistage process of osteogenesis, hMSC-mediated repair might be maximal at a specific time point of healing. Using a mouse model of calvarial healing, we demonstrate that the osteo-repair capacity of hMSCs can be substantially augmented by treatment with an inhibitor of peroxisome proliferator-activated receptor γ, but efficacy is confined to the rapid osteogenic phase. Upon entry into the bone-remodeling phase, hMSC retention signals are lost, resulting in truncation of healing. To solve this limitation, we prepared a scaffold consisting of hMSC-derived extracellular matrix (ECM) containing the necessary biomolecules for extended site-specific hMSC retention. When inhibitor-treated hMSCs were coadministered with ECM, they remained at the injury, well into the remodeling phase of healing, which resulted in reproducible and complete repair of critical-sized bone defects in mice in 3 weeks. These data suggest that hMSC-derived ECM and inhibitor-treated hMSCs could be used at optimal times to substantially and reproducibly improve bone repair.

Case study with unique laboratory analysis.To present a potentially serious adverse event that may occur in unique individuals when using recombinant human bone morphogenetic protein-2 (rhBMP-2) to augment fusion in posterior cervical spine surgery.The use of rhBMP-2 to augment posterior cervical decompression and fusion has not been approved by the Food and Drug Administration but has been advocated as safe to use by case series studies and multiple authors.A 66-year-old patient with myelopathy underwent posterior cervical decompression and fusion, using rhBMP-2 as a bone graft substitute. The patient had complete resolution of symptoms after surgery until day 6, when she experienced increasing pain and weakness. T2 magnetic resonance images revealed a high intensity fluid collection compressing the cervical cord posteriorly. Emergent decompression was performed and the patient improved until postoperative day 12 when the same clinical scenario occurred. Symptoms again improved with surgical debridement. The clear, nonsanguineous fluid was sent for a quantitative cytokine panel each time. The case is reviewed with specific reference to the evolving literature regarding rhBMP-2 use in the spine, and the findings of seroma analysis.The fluid analysis of the seroma fluid at the time of both debridements showed impressive elevations in inflammatory cytokines, especially IL-6 and IL-8.Acute inflammatory reactions to rhBMP-2 can occur in the posterior cervical spine and can lead to significant morbidity. Host factors, BMP-2 dosage, and carrier factors all likely play a role in these complex reactions and must be considered every time an "off label" usage of rhBMP-2 is considered. More study is clearly indicated.