The Impact of Preoperative Adaptive Training on Postoperative Outcomes in Lumbar Spine Fusion Surgery for Lumbar Disc Herniation: A Retrospective Analysis.

Purpose: Lumbar disc herniation, often treated with surgical decompression when conservative measures fail, presents challenges due to prolonged prone positioning in surgeries. This retrospective study evaluates the benefits of preoperative adaptive training to mitigate post-surgical physiological changes. Patients and Methods: A review of medical records from June 2021 to March 2023 identified 170 patients unresponsive to conservative treatments. Grouped into adaptive training and control groups based on historical data, the former had undergone exercises to prepare for surgery and postoperative changes. Vital signs and VAS scores were extracted from patient records to assess training impact. Results: The adaptive training group demonstrated stabilized vital signs intraoperatively, with a notable improvement in surgical exposure compared to the control group. However, there were no significant differences in operative time or blood loss between the groups. Additionally, postoperative VAS scores showed no significant improvement in the adaptive training group at follow-up intervals of 14 days, 1 month, and 3 months post-operation, compared to the control group. Conclusion: Our study reveals that preoperative adaptive training stabilizes intraoperative blood pressure fluctuations in lumbar disc herniation surgeries. However, this stabilization does not significantly impact long-term postoperative pain management. This highlights the need for further research to explore comprehensive strategies that effectively combine preoperative training with postoperative care.

Vascular Dysfunction after Modeled Traumatic Brain Injury Is Preserved with Administration of Umbilical Cord Derived Mesenchymal Stromal Cells and Is Associated with Modulation of the Angiogenic Response.

Vascular dysfunction arising from blood-brain barrier (BBB) breakdown after traumatic brain injury (TBI) can adversely affect neuronal health and behavioral outcome. Pericytes and endothelial cells of the neurovascular unit (NVU) function collectively to maintain strict regulation of the BBB through tight junctions. Secondary injury mechanisms, such as pro-angiogenic signals that contribute to pericyte loss, can prolong and exacerbate primary vascular injury. Human umbilical cord perivascular cells (HUCPVCs) are a source of mesenchymal stromal cells (MSCs) that have been shown to reduce vascular dysfunction after neurotrauma. We hypothesized that the perivascular properties of HUCPVCs can reduce vascular dysfunction after modeled TBI by preserving the pericyte-endothelial interactions. Rats were subjected to a moderate fluid percussion injury (FPI) and intravenously infused with 1,500,000 HUCPVCs post-injury. At acute time points (24 h and 48 h) quantitative polymerase chain reaction (qPCR) analysis demonstrated that the gene expression of angiopoietin-2 was increased with FPI and reduced with HUCPVCs. Immunofluorescent assessment of RECA-1 (endothelial cells) and platelet-derived growth factor receptors (PDGFR-ß) (pericytes) revealed that capillary and pericyte densities as well as the co-localization of the two cells were decreased with FPI and preserved with HUCPVC administration. These acute HUCPVC-mediated protective effects were associated with less permeability to Evan's blue dye and increased expression of the tight junction occludin, suggesting less vascular leakage. Further, at 4 weeks post-injury, HUCPVC administration was associated with reduced anxiety and decreased ß-amyloid precursor protein (ß-APP) accumulation. In summary, HUCPVCs promoted pericyte-endothelial barrier function that was associated with improved long-term outcome.

Patient Perceptions of SARS-CoV-2 Exposure Risk and Association With Continuity of Ophthalmic Care.

Importance: Patient perceptions regarding the risks of obtaining in-person ophthalmic care during the coronavirus disease 2019 (COVID-19) pandemic may affect adherence to recommended treatment plans and influence visual outcomes. A deeper understanding of patient perspectives will inform strategies to optimize adherence with vision-preserving therapies. Objective: To evaluate perceptions of COVID-19 exposure risk and their association with appointment attendance among patients at high risk of both reversible and irreversible vision loss from lapses in care. Design, Setting, and Participants: This survey study included a nonvalidated telephone survey designed in April and May of 2020 and a retrospective medical record review conducted in parallel with survey administration from May 22 to August 18, 2020. Participants were recruited from 2 tertiary eye care centers (Emory Eye Center in Atlanta, Georgia, and W.K. Kellogg Eye Center in Ann Arbor, Michigan). The study included a random sample of patients with diagnoses of exudative age-related macular degeneration (AMD) or diabetic retinopathy (DR) who received an intravitreal injection between January 6 and March 13, 2020, and were scheduled for a second injection between March 13 and May 6, 2020. Main Outcomes and Measures: Association between perceptions regarding COVID-19 risks and loss to follow-up. Results: Of 1004 eligible patients, 423 (42%) were successfully contacted, and 348 (82%) agreed to participate (participants' mean [SD] age, 75 [12] years; 195 women [56%]; 287 White [82%] patients). Respondents had a mean (SD) of 2.7 (1.1) comorbidities associated with severe COVID-19, and 77 (22%) knew someone with COVID-19. Of all respondents, 163 (47%) were very concerned or moderately concerned about vision loss from missed treatments during the pandemic. Although 208 (60%) believed the COVID-19 virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exposure at the eye clinic was extremely unlikely or unlikely, 49 (14%) believed it was extremely likely or likely. Seventy-eight participants (22%) were lost to follow-up. Concern regarding COVID-19 exposure during clinic visits (odds ratio [OR], 3.9; 95% CI, 1.8-8.4) and diagnosis of DR (vs AMD) (OR, 8.130; 95% CI, 3.367-20.408) were associated with an increase in likelihood of loss to follow-up. Conclusions and Relevance: Among patients at high risk for vision loss from lapses in care, many expressed concerns regarding the effect of the pandemic on their ability to receive timely care. Survey results suggest that fear of SARS-CoV-2 exposure was associated with a roughly 4-fold increase in the odds of patient loss to follow-up. These results support the potential importance of clearly conveying infection-control measures.

1-Methylnicotinamide is an immune regulatory metabolite in human ovarian cancer.

Immune regulatory metabolites are key features of the tumor microenvironment (TME), yet with a few exceptions, their identities remain largely unknown. Here, we profiled tumor and T cells from tumor and ascites of patients with high-grade serous carcinoma (HGSC) to uncover the metabolomes of these distinct TME compartments. Cells within the ascites and tumor had pervasive metabolite differences, with a notable enrichment in 1-methylnicotinamide (MNA) in T cells infiltrating the tumor compared with ascites. Despite the elevated levels of MNA in T cells, the expression of nicotinamide N-methyltransferase, the enzyme that catalyzes the transfer of a methyl group from S-adenosylmethionine to nicotinamide, was restricted to fibroblasts and tumor cells. Functionally, MNA induces T cells to secrete the tumor-promoting cytokine tumor necrosis factor alpha. Thus, TME-derived MNA contributes to the immune modulation of T cells and represents a potential immunotherapy target to treat human cancer.

Inhibiting ULK1 kinase decreases autophagy and cell viability in high-grade serous ovarian cancer spheroids.

Metastasis in high-grade serous ovarian cancer (HGSOC) occurs through an unconventional route that involves exfoliation of cancer cells from primary tumors and peritoneal dissemination via multicellular clusters or spheroids. Previously, we demonstrated autophagy induction in HGSOC spheroids grown in vitro and in spheroids collected from ovarian cancer patient ascites; thus, we speculate that autophagy may contribute to spheroid cell survival and overall disease progression. Hence, in this study we sought to evaluate whether ULK1 (unc-51-like kinase-1), a serine-threonine kinase critical for stress-induced autophagy, is important for autophagy regulation in HGSOC spheroids. We demonstrate that HGSOC spheroids have increased ULK1 protein expression that parallels autophagy activation. ULK1 knockdown increased p62 accumulation and decreased LC3-II/I ratio in HGSOC spheroids. In addition, knocking down ATG13, a protein that regulates ULK1 activity via complex formation, phenocopied our ULK1 knockdown results. HGSOC spheroids were blocked in autophagic flux due to ULK1 and ATG13 knockdown as determined by an mCherry-eGFP-LC3B fluorescence reporter. These observations were recapitulated when HGSOC spheroids were treated with an ULK1 kinase inhibitor, MRT68921. Autophagy regulation in normal human fallopian tube epithelial FT190 cells, however, may bypass ULK1, since MRT68921 reduced viability in HGSOC spheroids but not in FT190 cells. Interestingly, ULK1 mRNA expression is negatively correlated with patient survival among stage III and stage IV serous ovarian cancer patients. As we observed using established HGSOC cell lines, cultured spheroids using our new, patient-derived HGSOC cells were also sensitive to ULK1 inhibition and demonstrated reduced cell viability to MRT68921 treatment. These results demonstrate the importance of ULK1 for autophagy induction in HGSOC spheroids and therefore justifies further evaluation of MRT68921, and other novel ULK1 inhibitors, as potential therapeutics against metastatic HGSOC.

Axon Degeneration Is Rescued with Human Umbilical Cord Perivascular Cells: A Potential Candidate for Neuroprotection After Traumatic Brain Injury.

Traumatic brain injury (TBI) leads to delayed secondary injury events consisting of cellular and molecular cascades that exacerbate the initial injury. Human umbilical cord perivascular cells (HUCPVCs) secrete neurotrophic and prosurvival factors. In this study, we examined the effects of HUCPVC in sympathetic axon and cortical axon survival models and sought to determine whether HUCPVC provide axonal survival cues. We then examined the effects of the HUCPVC in an in vivo fluid percussion injury model of TBI. Our data indicate that HUCPVCs express neurotrophic and neural survival factors. They also express and secrete relevant growth and survival proteins when cultured alone, or in the presence of injured axons. Coculture experiments indicate that HUCPVCs interact preferentially with axons when cocultured with sympathetic neurons and reduce axonal degeneration. Nerve growth factor withdrawal in axonal compartments resulted in 66 ± 3% axon degeneration, whereas HUCPVC coculture rescued axon degeneration to 35 ± 3%. Inhibition of Akt (LY294002) resulted in a significant increase in degeneration compared with HUCPVC cocultures (48 ± 7% degeneration). Under normoxic conditions, control cultures showed 39 ± 5% degeneration. Oxygen glucose deprivation (OGD) resulted in 58 ± 3% degeneration and OGD HUCPVC cocultures reduced degeneration to 34 ± 5% (p < 0.05). In an in vivo model of TBI, immunohistochemical analysis of NF200 showed improved axon morphology in HUCPVC-treated animals compared with injured animals. These data presented in this study indicate an important role for perivascular cells in protecting axons from injury and a potential cell-based therapy to treat secondary injury after TBI.

Soluble CD93 is an apoptotic cell opsonin recognized by αx ß2.

Efferocytosis is essential for homeostasis and prevention of the inflammatory and autoimmune diseases resulting from apoptotic cell lysis. CD93 is a transmembrane glycoprotein previously implicated in efferocytosis, with mutations in CD93 predisposing patients to efferocytosis-associated diseases. CD93 is a cell surface protein, which is proteolytically shed under inflammatory conditions, but it is unknown how CD93 mediates efferocytosis or whether its efferocytic activity is mediated by the soluble or membrane-bound form. Herein, using cell lines and human monocytes and macrophages, we demonstrate that soluble CD93 (sCD93) potently opsonizes apoptotic cells but not a broad range of microorganisms, whereas membrane-bound CD93 has no phagocytic, efferocytic, or tethering activity. Using mass spectrometry, we identified αx ß2 as the receptor that recognizes sCD93, and via deletion mutagenesis determined that sCD93 binds to apoptotic cells via its C-type lectin-like domain and to αx ß2 by its EGF-like repeats. The bridging of apoptotic cells to αx ß2 markedly enhanced efferocytosis by macrophages and was abrogated by αx ß2 knockdown. Combined, these data elucidate the mechanism by which CD93 regulates efferocytosis and identifies a previously unreported opsonin-receptor system utilized by phagocytes for the efferocytic clearance of apoptotic cells.

Bone-Marrow-Derived Endothelial Progenitor Cell Treatment in a Model of Lateral Fluid Percussion Injury in Rats: Evaluation of Acute and Subacute Outcome Measures.

Traumatic brain injury (TBI) continues to be a serious health care issue while therapies to treat TBI remain elusive. Promising results from the use of endothelial progenitor cells (EPCs) in numerous disease states highlight the pleiotropic capacity of this cell type. We have previously demonstrated that EPC-conditioned media reduces axonal degeneration subsequent to in vitro oxygen-glucose deprivation insult and concurrently improves white matter and microvascular outcome in vivo after mid-line fluid percussion injury. In the current study, we evaluated the effectiveness of allogeneic endothelial cells derived from rat bone marrow on microvascular recovery and neuronal sparing after lateral fluid percussion injury. We observed reduced expression of activated caspase-3 and poly (ADP-ribose) polymerase cleavage at 72 h post-injury. Subacute injury assessments at 30 days post-injury using immunohistochemistry indicated nonsignificant effects on microvascular outcome and neuronal cell density in the hippocampus. Behavioral testing using the Morris Water Maze and rotarod demonstrated significant improvement in locomotor function, as measured by the rotarod task, but no significant differences in spatial memory ability. The data suggest that EPCs contribute to improvements in the early phase of secondary injury through inhibition of apoptosis whereas the effects on longer-term recovery were less clearly defined. There is potential in the use of EPCs to treat secondary injury post-TBI; however, optimization of their effects through increased duration or homing capacities remains to be examined.

A Novel Model of Traumatic Brain Injury in Adult Zebrafish Demonstrates Response to Injury and Treatment Comparable with Mammalian Models.

Traumatic brain injury (TBI) is a leading cause of death and morbidity in industrialized countries with considerable associated health care costs. The cost and time associated with pre-clinical development of TBI therapeutics is lengthy and expensive with a poor track record of successful translation to the clinic. The zebrafish is an emerging model organism in research with unique technical and genomic strengths in the study of disease and development. Its high degree of genetic homology and cell signaling pathways relative to mammalian species and amenability to high and medium throughput assays has potential to accelerate the rate of therapeutic drug identification. Accordingly, we developed a novel closed-head model of TBI in adult zebrafish using a targeted, pulsed, high-intensity focused ultrasound (pHIFU) to induce mechanical injury of the brain. Western blot results indicated altered microtubule and neurofilament expression as well as increased expression of cleaved caspase-3 and beta APP (ß-APP; p < 0.05). We used automated behavioral tracking software to evaluate locomotor deficits 24 and 48 h post-injury. Significant behavioral impairment included decreased swim distance and velocity (p < 0.05), as well as heightened anxiety and altered group social dynamics. Responses to injury were pHIFU dose-dependent and modifiable with MK-801, MDL-28170, or temperature modulation. Together, results indicate that the zebrafish exhibits responses to injury and intervention similar to mammalian TBI pathophysiology and suggest the potential for use to rapidly evaluate therapeutic compounds with high efficiency.

ATRIP Deacetylation by SIRT2 Drives ATR Checkpoint Activation by Promoting Binding to RPA-ssDNA.

The ataxia telangiectasia-mutated and Rad3-related (ATR) kinase checkpoint pathway maintains genome integrity; however, the role of the sirtuin 2 (SIRT2) acetylome in regulating this pathway is not clear. We found that deacetylation of ATR-interacting protein (ATRIP), a regulatory partner of ATR, by SIRT2 potentiates the ATR checkpoint. SIRT2 interacts with and deacetylates ATRIP at lysine 32 (K32) in response to replication stress. SIRT2 deacetylation of ATRIP at K32 drives ATR autophosphorylation and signaling and facilitates DNA replication fork progression and recovery of stalled replication forks. K32 deacetylation by SIRT2 further promotes ATRIP accumulation to DNA damage sites and binding to replication protein A-coated single-stranded DNA (RPA-ssDNA). Collectively, these results support a model in which ATRIP deacetylation by SIRT2 promotes ATR-ATRIP binding to RPA-ssDNA to drive ATR activation and thus facilitate recovery from replication stress, outlining a mechanism by which the ATR checkpoint is regulated by SIRT2 through deacetylation.

From Albania to Zambia: travel back to country of origin as a goal of care for terminally ill patients.

BACKGROUND: With unprecedented levels of international migration, physicians in the United States may care for terminally ill patients who have strong connections to their country of origin and such patients may desire to return in the final stages of life. OBJECTIVE: In this study, we analyzed how often terminally ill patients cited travel to country of origin as a goal of care, how often travel occurred, and factors associated with successful travel. DESIGN: A retrospective chart review from January 1, 2005 through May 1, 2007. SETTING/SUBJECTS: All foreign-born patients seen by a palliative care consultation service, including inpatient and outpatient consultations, in an urban safety-net health system in the United States. MEASUREMENTS: We determined whether patients expressed a desire to travel to their country of origin and the factors, including demographics and functional status associated with travel. RESULTS: Of 336 foreign-born patients, 129 (38%) expressed a desire to travel to their country of origin; 60 (47%) successfully returned to 24 unique countries. Countries to which the largest number of patients returned were Mexico (n=14), Poland (n=11), and the Philippines (n=7). Although patients with the best functional status were most likely to travel successfully, 16 (31%) who wanted to travel despite having the worst functional status (Eastern Cooperative Oncology Group [ECOG] score indicating confinement to bed or chair) traveled successfully. There were no deaths en route or flight diversions due to medical crisis; all trips were made on regularly scheduled commercial airline flights. CONCLUSIONS: A substantial proportion of patients in our cohort expressed a desire to return to their country of origin. We facilitated successful travel for nearly half of these patients. Our findings identify the need to include travel back to country of origin in the framework of planning care for terminally ill patients.

A gemcitabine sensitivity screen identifies a role for NEK9 in the replication stress response.

The Replication Stress Response (RSR) is a signaling network that recognizes challenges to DNA replication and coordinates diverse DNA repair and cell-cycle checkpoint pathways. Gemcitabine is a nucleoside analogue that causes cytotoxicity by inducing DNA replication blocks. Using a synthetic lethal screen of a RNAi library of nuclear enzymes to identify genes that when silenced cause gemcitabine sensitization or resistance in human triple-negative breast cancer cells, we identified NIMA (never in mitosis gene A)-related kinase 9 (NEK9) as a key component of the RSR. NEK9 depletion in cells leads to replication stress hypersensitivity, spontaneous accumulation of DNA damage and RPA70 foci, and an impairment in recovery from replication arrest. NEK9 protein levels also increase in response to replication stress. NEK9 complexes with CHK1, and moreover, NEK9 depletion impairs CHK1 autophosphorylation and kinase activity in response to replication stress. Thus, NEK9 is a critical component of the RSR that promotes CHK1 activity, maintaining genome integrity following challenges to DNA replication.

CHD7 expression predicts survival outcomes in patients with resected pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with poor outcomes with current therapies. Gemcitabine is the primary adjuvant drug used clinically, but its effectiveness is limited. In this study, our objective was to use a rationale-driven approach to identify novel biomarkers for outcome in patients with early-stage resected PDAC treated with adjuvant gemcitabine. Using a synthetic lethal screen in human PDAC cells, we identified 93 genes, including 55 genes linked to DNA damage responses (DDR), that demonstrated gemcitabine sensitization when silenced, including CHD7, which functions in chromatin remodeling. CHD7 depletion sensitized PDAC cells to gemcitabine and delayed their growth in tumor xenografts. Moreover, CHD7 silencing impaired ATR-dependent phosphorylation of CHK1 and increased DNA damage induced by gemcitabine. CHD7 was dysregulated, ranking above the 90th percentile in differential expression in a panel of PDAC clinical specimens, highlighting its potential as a biomarker. Immunohistochemical analysis of specimens from 59 patients with resected PDAC receiving adjuvant gemcitabine revealed that low CHD7 expression was associated with increased recurrence-free survival (RFS) and overall survival (OS), in univariate and multivariate analyses. Notably, CHD7 expression was not associated with RFS or OS for patients not receiving gemcitabine. Thus, low CHD7 expression was correlated selectively with gemcitabine sensitivity in this patient population. These results supported our rationale-driven strategy to exploit dysregulated DDR pathways in PDAC to identify genetic determinants of gemcitabine sensitivity, identifying CHD7 as a novel biomarker candidate to evaluate further for individualizing PDAC treatment.

Bone marrow-derived endothelial progenitor cells protect postischemic axons after traumatic brain injury.

White matter sparing after traumatic brain injury (TBI) is an important predictor of survival and outcome. Blood vessels and axons are intimately associated anatomically and developmentally. Neural input is required for appropriate vascular patterning, and vascular signaling is important for neuron development and axon growth. Owing to this codependence between endothelial cells and axons during development and the contribution of endothelial progenitor cells (EPCs) in ischemic injury, we hypothesized that EPCs are important in axonal survival after TBI. We examined the effects of allogenic-cultured EPCs on white matter protection and microvascular maintenance after midline fluid percussion injury in adult Sprague-Dawley rats. We used two in vitro models of injury, mechanical stretch and oxygen-glucose deprivation (OGD), to examine the effects of EPCs on the mechanical and ischemic components of brain trauma, respectively. Our results indicate that EPCs improve the white matter integrity and decrease capillary breakdown after injury. Cultured cortical neurons exposed to OGD had less axon degeneration when treated with EPC-conditioned media, whereas no effect was seen in axons injured by mechanical stretch. The results indicate that EPCs are important for the protection of the white matter after trauma and represent a potential avenue for therapy.

Treatment of traumatic brain injury using zinc-finger protein gene therapy targeting VEGF-A.

Vascular endothelial growth factor (VEGF) plays a role in angiogenesis and has been shown to be neuroprotective following central nervous system trauma. In the present study we evaluated the pro-angiogenic and neuroprotective effects of an engineered zinc-finger protein transcription factor transactivator targeting the vascular endothelial growth factor A (VEGF-ZFP). We used two virus delivery systems, adeno-virus and adeno-associated virus, to examine the effects of early and delayed VEGF-A upregulation after brain trauma, respectively. Male Sprague-Dawley rats were subject to a unilateral fluid percussion injury (FPI) of moderate severity (2.2-2.5 atm) followed by intracerebral microinjection of either adenovirus vector (Adv) or an adeno-associated vector (AAV) carrying the VEGF-ZFP construct. Adv-VEGF-ZFP-treated animals had significantly fewer TUNEL positive cells in the injured penumbra of the cortex (p<0.001) and hippocampus (p=0.001) relative to untreated rats at 72 h post-injury. Adv-VEGF-ZFP treatment significantly improved fEPSP values (p=0.007) in the CA1 region relative to injury alone. Treatment with AAV2-VEGF-ZFP resulted in improved post-injury microvascular diameter and improved functional recovery on the balance beam and rotarod task at 30 days post-injury. Collectively, the results provide supportive evidence for the concept of acute and delayed treatment following TBI using VEGF-ZFP to induce angiogenesis, reduce cell death, and enhance functional recovery.

A potential role for inducible nitric oxide synthase in the cerebral response to acute hemodilution.

PURPOSE: Acute anemia increases the cerebral expression of hypoxic molecules including neuronal nitric oxide synthase (nNOS) and hypoxia inducible factor-1alpha (HIF-1alpha). This study assessed the effects of acute hemodilution on inducible NOS (iNOS) and systemic inflammatory cytokines. METHODS: Anesthetized rats (n = 5-7 per group) underwent 50% hemodilution with pentastarch, whole blood exchange or no fluid exchange. Cerebral cortical nNOS and iNOS protein levels were characterized using Western blot analysis and immunostaining (1 and 18 h). Plasma cytokine levels were assessed by enzyme-linked immunosorbent assay (1, 4, and 18 h). Data were analyzed by two-way analysis of variance to determine significance (P < 0.05, mean +/- SD). RESULTS: No differences in mean arterial blood pressure or arterial blood gases were observed between groups after hemodilution. A comparable hemoglobin target (approximately 70 g . L(-1)) was achieved in all groups following hemodilution. Cerebral cortical iNOS protein levels were increased in anemic rats, relative to controls. The nNOS protein levels increased to a greater degree (P < 0.05 for both). Immunostaining demonstrated that iNOS localized to endothelium, glial fibrillary acidic protein (GFAP) positive (astrocytes) and GFAP negative cells within the brain. Plasma cytokine levels (tumour necrosis factor alpha, interleukin (IL)-1beta and IL-6) increased transiently, to the same levels, in both control and hemodiluted rats. CONCLUSIONS: Cerebral cortical iNOS and nNOS protein levels were both increased in anemic rats. The nNOS response was predominant. This suggests that NOS-derived NO may be an important signalling pathway which is activated in the brain during anemia. These cellular responses could maintain cerebral homeostasis, or contribute to neuronal injury, during acute hemodilutional anemia.

A reappraisal on the ability of leptin to induce fever.

Leptin is often regarded as a mediator of fever, even though an in-depth analysis of the dose-dependent effects of leptin on body temperature (T(b)), pro-inflammatory cytokines, and circulating leptin has never been performed. In the present study, such an analysis was performed in rats that were food deprived (lower baseline levels of leptin) or free feeding (higher baseline levels of leptin). In a relatively cool environment (22 degrees C), rats deprived of food for 24 h exhibited mild (approximately 0.5 degrees C) hypothermia. Leptin infusion (250 microg/kg iv) elevated the T(b) of the food-deprived rats to a normothermic level, an effect that peaked (120 min post-infusion) when plasma leptin was at a level (approximately 8 ng/mL) often found in leptin-responsive subjects. Increasing the leptin dose to 1000 microg/kg did not produce any further (febrile) elevation in the T(b) of food-deprived rats. The anti-hypothermic effect of leptin in food-deprived rats was not associated with any rise in the plasma levels of the pro-inflammatory cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-6. In free-feeding rats kept in a cooler (22 degrees C) or warmer (28 degrees C) environment, leptin infusion failed to alter T(b) or to produce any surge in plasma TNF-alpha or IL-6, even when the dose infused (3500 microg/kg iv) resulted in excessive, non-physiological rises in plasma leptin (approximately 542 ng/mL at 30 min; approximately 75 ng/mL at 120 min post-infusion). In contrast, free-feeding rats in the same experimental set-up were able to respond to a low dose (2 microg/kg iv) of IL-1beta with a typical biphasic fever, which was associated with surges in plasma TNF-alpha and IL-6. Collectively, our data show that an acute rise in plasma leptin to a level within or fairly above the physiological range does not induce fever. These results challenge the idea that leptin may be a mediator of fever.

Effects of resuscitation fluid on neurologic physiology after cerebral trauma and hemorrhage.

BACKGROUND: The current standard of care for fluid resuscitation of hemorrhagic hypotensive patients involves the use of crystalloid solutions. Traumatic brain injury (TBI) is often associated with hemorrhage and hypotension, which can contribute significantly to morbidity and mortality. Guidelines for the choice of fluid resuscitation and the use of red blood cell transfusions are not yet clear in the context of brain injury. METHODS: Various fluid resuscitation strategies were evaluated in Sprague-Dawley rats using fresh blood, normal saline, hypertonic saline, and albumin fluid resuscitation protocols. Mean arterial blood pressure (MAP) and cerebral oximetry were assessed in hemorrhaged groups and the mean population spike amplitudes (PSA) from the hippocampus were examined in fluid percussion injured (FPI) animals subject to hemorrhage and fluid resuscitation. RESULTS: MAP in control animals, hemorrhage and hemorrhage + albumin treated groups was 82.4 +/- 1.5 mm Hg, 55.7 +/- 1.5 mm Hg, and 97.0 +/- 3.4 mm Hg, respectively. Arterial PaO2 was higher in albumin-treated animals relative to other fluid alternatives. Regional tissue oxygen tension (PbrO2) levels in hemorrhaged animals reached significantly higher levels in albumin treated group compared with in normal saline and hypertonic saline (p < 0.001, p = 0.034, respectively). After FPI+hemorrhage, PSA values in albumin- resuscitated animals were significantly higher than in normal saline-resuscitated animals (p = 0.012). CONCLUSIONS: The results of normal saline resuscitation, relative to other fluid alternatives, suggest that a re-evaluation of current treatment strategies in hemorrhagic hypotensive TBI patients is warranted. Albumin demonstrated the greatest beneficial effects on neurophysiology endpoints over crystalloid alternatives. These data suggests that albumin resuscitation may play an important role in the treatment of hemorrhagic hypotension and TBI.

Calpain inhibitor MDL-28170 reduces the functional and structural deterioration of corpus callosum following fluid percussion injury.

It is known that calpain activation is involved in human traumatic brain injury (TBI) and that calpain inhibition can have neuroprotective effects on both gray matter and white matter injury of TBI models. However, the role of calpain activation in the corpus callosum remains unclear and requires elucidation given its potential clinical relevance. We evaluated the neuroprotective effects of calpain inhibitor MDL-28170 on corpus callosum function and structural destruction using a fluid percussion injury (FPI) model. The therapeutic time window for a single administration of MDL-28170 was up to 4 h post injury in protecting the corpus callosum structural integrity, and up to 30 min in protecting the axonal function evaluated 1 day following injury. When given 30 min prior injury, MDL-28170 showed neuroprotective effects that lasted up to 7 days. However, 30 min post injury administration of the drug afforded neuroprotection only up to 3 days. In contrast, two additional reinforcement injections at 24 and 48 h in addition to 30 min post FPI significantly protected both axonal function and structural integrity that lasted 14 days following FPI. Our data indicated that calpain inhibitor MDL-28170 is an effective neuroprotectant for axonal injury in corpus callosum following FPI with a therapeutic time window up to 4 hours. Although delayed treatment (2 or 4 h post FPI) was effective in protecting the axonal structure, the axons saved may not be as functional as normal fibers. Multiple drug administrations may be necessary for achieving a persisting effectiveness of this compound.

Increased expression of HIF-1alpha, nNOS, and VEGF in the cerebral cortex of anemic rats.

This study tested the hypothesis that specific hypoxic molecules, including hypoxia-inducible factor-1alpha (HIF-1alpha), neuronal nitric oxide synthase (nNOS), and vascular endothelial growth factor (VEGF), are upregulated within the cerebral cortex of acutely anemic rats. Isoflurane-anesthetized rats underwent acute hemodilution by exchanging 50% of their blood volume with pentastarch. Following hemodilution, mean arterial pressure and arterial Pa(O(2)) values did not differ between control and anemic rats while the hemoglobin concentration decreased to 57 +/- 2 g/l. In anemic rats, cerebral cortical HIF-1alpha protein levels were increased, relative to controls (1.7 +/- 0.5-fold, P < 0.05). This increase was associated with an increase in mRNA levels for VEGF, erythropoietin, CXCR4, iNOS, and nNOS (P < 0.05 for all), but not endothelial NOS. Cerebral cortical nNOS and VEGF protein levels were increased in anemic rats, relative to controls (2.0 +/- 0.2- and 1.5 +/- 0.4-fold, respectively, P < 0.05 for both). Immunohistochemistry demonstrated increased HIF-1alpha and VEGF staining in perivascular regions of the anemic cerebral cortex and an increase in the number of nNOS-positive cerebral cortical cells (3.2 +/- 1.0-fold, P < 0.001). The nNOS-positive cells costained with the neuronal marker, Neu-N, but not with the astrocytic marker glial fibrillary acidic protein (GFAP). These nNOS-positive neurons frequently sent axonal projections toward cerebral blood vessels. Conversely, VEGF immunostaining colocalized with both neuronal (NeuN) and astrocytic markers (GFAP). In conclusion, acute normotensive, normoxemic hemodilution increased the levels of HIF-1alpha protein and mRNA for HIF-1-responsive molecules. nNOS and VEGF protein levels were also increased within the cerebral cortex of anemic rats at clinically relevant hemoglobin concentrations.