The immunomodulatory effect of oral NaHCO3 is mediated by the splenic nerve: multivariate impact revealed by artificial neural networks.

Stimulation of the inflammatory reflex (IR) is a promising strategy for treating systemic inflammatory disorders. Recent studies suggest oral sodium bicarbonate (NaHCO3) as a potential activator of the IR, offering a safe and cost-effective treatment approach. However, the mechanisms underlying NaHCO3-induced anti-inflammatory effects remain unclear. We investigated whether oral NaHCO3's immunomodulatory effects are mediated by the splenic nerve. Female rats received NaHCO3 or water (H2O) for four days, and splenic immune markers were assessed using flow cytometry. NaHCO3 led to a significant increase (p < 0.05, and/or partial eta squared > 0.06) in anti-inflammatory markers, including CD11bc + CD206 + (M2-like) macrophages, CD3 + CD4 + FoxP3 + cells (Tregs), and Tregs/M1-like ratio. Conversely, proinflammatory markers, such as CD11bc + CD38 + TNFα + (M1-like) macrophages, M1-like/M2-like ratio, and SSChigh/SSClow ratio of FSChighCD11bc + cells, decreased in the spleen following NaHCO3 administration. These effects were abolished in spleen-denervated rats, suggesting the necessity of the splenic nerve in mediating NaHCO3-induced immunomodulation. Artificial neural networks accurately classified NaHCO3 and H2O treatment in sham rats but failed in spleen-denervated rats, highlighting the splenic nerve's critical role. Additionally, spleen denervation independently influenced Tregs, M2-like macrophages, Tregs/M1-like ratio, and CD11bc + CD38 + cells, indicating distinct effects from both surgery and treatment. Principal component analysis (PCA) further supported the separate effects. Our findings suggest that the splenic nerve transmits oral NaHCO3-induced immunomodulatory changes to the spleen, emphasizing NaHCO3's potential as an IR activator with therapeutic implications for a wide spectrum of systemic inflammatory conditions.

Mandible Reconstruction in a Rural Population: Comparison of Radial Forearm and Free Fibula Flap Outcomes.

Comparison of microsurgical reconstructive options after mandible resection is limited in the literature. Fibula free flaps (FFFs) can be costly and have timing limitations, but dental restoration can be performed, with varied reported rates of completion. The radial forearm free flap (RFFF) with mandible plating may be an alternative in select populations. The purpose of this study was to determine if the RFFF has similar outcomes to the FFF for mandible reconstruction in a rural population. A retrospective review of patients who underwent mandibulectomy from 2017 to 2021 at a single tertiary-care academic institution was performed. Those with FFF or RFFF reconstruction were included. Mandible defects were classified using the Jewer-Boyd H-C-L system. Sixty-eight patients were included with 53 undergoing FFF and 15 undergoing RFFF. Immediate reconstruction was significantly more common with RFFF than FFF (100% versus 64.2%; P =0.01). Lateral mandible defects were most common among both groups (52.9% FFF versus 73.3% RFFF; P =0.04). Osseous defect length was similar (9.5 cm FFF versus 7.7 cm RFFF; P =0.07), but soft tissue defect size was significantly larger in the RFFF group (28.6 cm 2 versus 15.3 cm 2 ; P =0.01). Complication rates (47.1% FFF versus 46.7% RFFF; P =0.98) and disease-free status at last follow-up (96.2% FFF versus 80.0% RFFF; P =0.06) were similar. Dental restoration occurred in 21.3% of patients undergoing FFF. Patients undergoing RFFF or FFF reconstruction after mandibulectomy had similar surgical and disease outcomes, with a low rate of completed dental restoration after FFF. Our findings suggest RFFF is a reasonable alternative to FFF for mandible reconstruction in select patients.

Neuronal BC RNA Transport Impairments Caused by Systemic Lupus Erythematosus Autoantibodies.

The etiology of the autoimmune disorder systemic lupus erythematosus (SLE) remains poorly understood. In neuropsychiatric SLE (NPSLE), autoimmune responses against neural self-antigens find expression in neurological and cognitive alterations. SLE autoantibodies often target nucleic acids, including RNAs and specifically RNA domains with higher-order structural content. We report that autoantibodies directed against neuronal regulatory brain cytoplasmic (BC) RNAs were generated in a subset of SLE patients. By contrast, anti-BC RNA autoantibodies (anti-BC abs) were not detected in sera from patients with autoimmune diseases other than SLE (e.g., rheumatoid arthritis or multiple sclerosis) or in sera from healthy subjects with no evidence of disease. SLE anti-BC abs belong to the IgG class of immunoglobulins and target both primate BC200 RNA and rodent BC1 RNA. They are specifically directed at architectural motifs in BC RNA 5' stem-loop domains that serve as dendritic targeting elements (DTEs). SLE anti-BC abs effectively compete with RNA transport factor heterogeneous nuclear ribonucleoprotein A2 (hnRNP A2) for DTE access and significantly diminish BC RNA delivery to synapto-dendritic sites of function. In vivo experiments with male BALB/c mice indicate that, upon lipopolysaccharide-induced opening of the blood-brain barrier, SLE anti-BC abs are taken up by CNS neurons where they significantly impede localization of endogenous BC1 RNA to synapto-dendritic domains. Lack of BC1 RNA causes phenotypic abnormalities including epileptogenic responses and cognitive dysfunction. The combined data indicate a role for anti-BC RNA autoimmunity in SLE and its neuropsychiatric manifestations.SIGNIFICANCE STATEMENT Although clinical manifestations of neuropsychiatric lupus are well recognized, the underlying molecular-cellular alterations have been difficult to determine. We report that sera of a subset of lupus patients contain autoantibodies directed at regulatory brain cytoplasmic (BC) RNAs. These antibodies, which we call anti-BC abs, target the BC RNA 5' domain noncanonical motif structures that specify dendritic delivery. Lupus anti-BC abs effectively compete with RNA transport factor heterogeneous nuclear ribonucleoprotein A2 (hnRNP A2) for access to BC RNAs. As a result, hnRNP A2 is displaced, and BC RNAs are impaired in their ability to reach synapto-dendritic sites of function. The results reveal an unexpected link between BC RNA autoantibody recognition and dendritic RNA targeting. Cellular RNA dysregulation may thus be a contributing factor in the pathogenesis of neuropsychiatric lupus.

Seizures induce obstructive apnea in DBA/2J audiogenic seizure-prone mice: Lifesaving impact of tracheal implants.

The mechanism(s) for sudden death in epilepsy (SUDEP) remain(s) unknown, but seizure spread to brainstem areas serving autonomic and respiratory function is critical. In a rat model, we established a mechanism for SUDEP that involves seizure-induced laryngospasm and obstructive apnea lasting until respiratory arrest. We hypothesized that DBA/2J mice, which display lethal audiogenic seizures, would be protected from death by implanting a tracheal T-tube as a surrogate airway. In a 2 × 2 design, mice were implanted with either open or closed tracheal T-tubes and treated with either low-dose ketamine/xylazine to moderate thoracic spasm during the tonic seizure phase or no drug. Animals receiving both treatments had the highest survival rate, followed by animals receiving the open tube without ketamine/xylazine. The odds ratio for survival was >20 higher with an open T-tube (odds ratio = 24.14). The impact of open tracheal tubes indicates that the mechanism of death in DBA/2J mice involves seizure-induced upper airway obstruction until respiratory arrest. These results, our rat work, and our demonstration of inspiratory effort-based electromyographic signals and electrocardiographic abnormalities in rats and humans suggest that seizure-induced laryngospasm and obstructive apnea directly link seizure activity to respiratory arrest in these sudden death examples.

Differentiated adipose-derived stem cell cocultures for bone regeneration in polymer scaffolds in vivo.

Critical-sized bone defects can lead to significant morbidity, and interventions are limited by the availability and donor-site morbidity of bone grafts. Polymer scaffolds seeded with cells have been explored to replace bone grafts. Adipose-derived stem cells have shown great promise for vascularization and osteogenesis of these constructs, and cocultures of differentiated stem cells are being explored to augment vessel and bone formation. Adipose-derived stem cells were differentiated into endothelial cells and osteoblasts, and in vitro studies showed increased proliferation of cocultured cells compared with undifferentiated adipose-derived stem cells and monocultures of endothelial cells and osteoblasts. The cells were seeded into polylactic acid gas-plasma-treated scaffolds as cocultures and monocultures and then implanted into critical-sized rat calvarial defects. The cocultures were in a 1:1 osteoblast to endothelial cell ratio. The increase in proliferation seen by the cocultured cells in vitro did not translate to increased vascularization and osteogenesis in vivo. In vivo, there were trends of increased vascularization in the endothelial cell group and increased osteogenesis in the osteoblast and endothelial monoculture groups, but no increase was seen in the coculture group compared with the undifferentiated adipose-derived stem cells. Endothelial cells enhance vascularization and osteoblast and endothelial cell monocultures enhance bone formation in the polymer scaffold. Predifferentiation of adipose-derived stem cells is promising for improving vascularization and osteogenesis in polymer scaffolds but requires future evaluation of coculture ratios to fully characterize this response.

Effect of polyester-based artificial tendons on movement biomechanics: A preliminary in vivo study.

Artificial tendons may be valuable clinical devices for replacing damaged or missing biological tendons. In this preliminary study, we quantified the effect of polyester-suture-based artificial tendons on movement biomechanics. New Zealand White rabbits underwent surgical replacement of either the Achilles (n = 2) or tibialis cranialis (TC, n = 2) biological tendons with artificial tendons. Once pre-surgery and weekly from 2 to 6 weeks post-surgery, we quantified hindlimb kinematics and ground contact pressures during the stance phase of hopping gait. Post-surgical movement biomechanics were either consistent or improved over time in both groups. However, the Achilles group had greater overall biomechanical and muscle deficits than the TC group. In the TC group, at 6 weeks post-surgery, foot angles were about 10° greater than those in healthy controls during the first 30 % of stance. At 6 weeks post-surgery, the Achilles group exhibited lesser (i.e., more dorsiflexed) ankle angles (minimum angle = 31.5 ± 9.4°) and vertical ground reaction forces (37.4 ± 2.6 %BW) during stance than those in healthy controls (65.0 ± 11.2° and 50.2 ± 8.3 %BW, respectively). Future studies are needed to quantify long-term biomechanical function with artificial tendons, the effect of artificial tendons on muscle function and structure, and the effect of formal rehabilitation.

The Impact of Travel Distance and Income on Breast Reconstruction after Mastectomy in a Rural Population.

Factors that influence breast reconstruction after mastectomy have been previously examined in national databases. The purpose of this study was to determine the impact of patient travel distance and income on breast reconstruction after mastectomy in a rural population. Methods: Retrospective review of mastectomy patients from 2017 to 2021 was performed from our prospectively enrolled tumor registry. Analysis included frequencies and percentages, descriptive statistics, χ 2 analysis, independent sample t tests, and multivariable analysis. Results: In total, 462 patients were included. Median BMI was 27.6 kg/m2, 96.1% of patients were White, and median age at diagnosis was 60.0 years. Reconstruction rate was 52.6%, and median length of follow-up was 24.6 months. No significant difference was found in the distance traveled by patients who underwent reconstruction (16.6 versus 16.7 miles; P = 0.94). Rates of reconstruction in patients who traveled 0-10 miles, 11-30 miles, and over 30 miles did not differ significantly (P = 0.16). Median household income was significantly different in reconstructed and nonreconstructed patients ($55,316.00 versus $51,629.00; P = 0.047). Rates of reconstruction were significantly higher in patients with median household income greater than $65,000 (P = 0.024). This difference was not significant on multivariable analysis. Conclusions: Travel distance did not significantly impact reconstruction rates after mastectomy, while household income did on univariable analysis. Studies at an institutional or regional level remain valuable, especially in populations that may not be accurately represented in larger database studies. Our findings highlight the importance of patient education, resource allocation, and multidisciplinary approach to breast cancer care, especially in the rural setting.

The Impact of Prior Breast Augmentation on Breast Reconstruction after Mastectomy.

The risk of women developing breast cancer after augmentation mammaplasty may be lower than the general population, with minimal current literature on breast reconstruction in this population. We sought to evaluate the impact of previous augmentation on postmastectomy breast reconstruction. Methods: Retrospective review of patients who underwent mastectomies from 2017 to 2021 at our institution was performed. Analysis included frequencies and percentages, descriptive statistics, chi-square analysis, and Fisher exact test. Results: Four hundred seventy patients were included, with average body mass index of 29.1 kg/m2, 96% identifying as White, and an average age at diagnosis of 59.3 years. Twenty (4.2%) patients had a prior breast augmentation. Reconstruction was performed in 80% of the previously augmented patients compared to 49.9% of nonaugmented patients (P = 0.01). Reconstruction was alloplastic in 100% of augmented and 88.7% of nonaugmented patients (P = 0.15). All reconstructed augmented patients underwent immediate reconstruction compared with 90.5% of nonaugmented patients (P = 0.37), and two-stage reconstruction was most common (75.0% versus 63.5%; P = 0.42). Of the previously augmented patients, 87.5% increased implant volume, 75% underwent same implant plane reconstruction, and 68.75% underwent same implant-type reconstruction as their augmentation. Conclusions: Previously augmented patients were more likely to undergo reconstruction after mastectomy at our institution. All reconstructed augmented patients underwent alloplastic reconstruction, with most performed immediately in staged fashion. Most patients favored silicone implants and maintained the same implant type and plane of reconstruction, with increased implant volume. Larger studies are required to further investigate these trends.

Effect of endothelial differentiated adipose-derived stem cells on vascularity and osteogenesis in poly(D,L-lactide) scaffolds in vivo.

Prevascularization of engineered bony constructs can potentially improve in vivo viability. However, the effect of endothelial cells on osteogenesis is unknown when placed in poly(D,L-lactide) (PLA) scaffolds alone. Adipose-derived stem cells (ASCs) have the ability to differentiate into both osteoblasts and endothelial cells by culture in specific media. We hypothesized that ASC-derived endothelial cells would improve vascularity with minimal contribution to bone formation when placed in scaffold alone. ASCs were successfully differentiated into endothelial cells (ASC-Endo) and osteoblasts (ASC-Osteo) using media supplemented with vascular endothelial growth factor and bone morphogenic protein 2, respectively. Tissue-engineered constructs were created with PLA matrices containing no cells (control), undifferentiated ASCs (ASCs), osteogenic-differentiated ASCs (ASC-Osteo), or endothelial differentiated ASCs (ASC-Endo), and these constructs were evaluated in critical-size Lewis rat calvarial defect model (n = 34). Eight weeks after implantation, the bone volume and microvessel population of bony constructs were evaluated by micro-computed tomography analysis and histologic staining. Bone volumes for ASCs and ASC-Osteo constructs, 0.7 and 0.91 mm(3), respectively, were statistically greater than that for ASC-Endo, 0.28 mm(3) (P < 0.05). There was no statistical difference between the PLA control (0.5 mm(3)) and ASC-Endo (0.28 mm(3)) constructs in bone formation. The percent area of microvessels within constructs was highest in the ASC-Endo group, although it did not reach statistical significance (0.065). Prevascularization of PLA scaffold with ASC-Endo cells will not increase bone formation by itself but may be used as a cell source for improving vascularization and potentially improving existing osteoblast function.

Autoimmune RNA dysregulation and seizures: therapeutic prospects in neuropsychiatric lupus.

Lupus autoimmunity frequently presents with neuropsychiatric manifestations, but underlying etiology remains poorly understood. Human brain cytoplasmic 200 RNA (BC200 RNA) is a translational regulator in neuronal synapto-dendritic domains. Here, we show that a BC200 guanosine-adenosine dendritic transport motif is recognized by autoantibodies from a subset of neuropsychiatric lupus patients. These autoantibodies impact BC200 functionality by quasi irreversibly displacing two RNA transport factors from the guanosine-adenosine transport motif. Such anti-BC autoantibodies, which can gain access to brains of neuropsychiatric lupus patients, give rise to clinical manifestations including seizures. To establish causality, naive mice with a permeabilized blood-brain barrier were injected with anti-BC autoantibodies from lupus patients with seizures. Animals so injected developed seizure susceptibility with high mortality. Seizure activity was entirely precluded when animals were injected with lupus anti-BC autoantibodies together with BC200 decoy autoantigen. Seizures are a common clinical manifestation in neuropsychiatric lupus, and our work identifies anti-BC autoantibody activity as a mechanistic cause. The results demonstrate potential utility of BC200 decoys for autoantibody-specific therapeutic interventions in neuropsychiatric lupus.

Feasibility of Implanting a Foot-Ankle Endoprosthesis within Skin in a Rabbit Model of Transtibial Amputation.

Prosthetic limbs that are completely implanted within skin (i.e., endoprostheses) could permit direct, physical muscle-prosthesis attachment to restore more natural sensorimotor function to people with amputation. The objective of our study was to test, in a rabbit model, the feasibility of replacing the lost foot after hindlimb transtibial amputation by implanting a novel rigid foot-ankle endoprosthesis that is fully covered with skin. We first conducted a pilot, non-survival surgery in two rabbits to determine the maximum size of the skin flap that could be made from the biological foot-ankle. The skin flap size was used to determine the dimensions of the endoprosthesis foot segment. Rigid foot-ankle endoprosthesis prototypes were successfully implanted in three rabbits. The skin incisions healed over a period of approximately 1 month after surgery, with extensive fur regrowth by the pre-defined study endpoint of approximately 2 months post surgery. Upon gross inspection, the skin surrounding the endoprosthesis appeared normal, but a substantial subdermal fibrous capsule had formed around the endoprosthesis. Histology indicated that the structure and thickness of the skin layers (epidermis and dermis) were similar between the operated and non-operated limbs. A layer of subdermal connective tissue representing the fibrous capsule surrounded the endoprosthesis. In the operated limb of one rabbit, the subdermal connective tissue layer was approximately twice as thick as the skin on the medial (skin = 0.43 mm, subdermal = 0.84 mm), ventral (skin = 0.80 mm, subdermal = 1.47 mm), and lateral (skin = 0.76 mm, subdermal = 1.42 mm) aspects of the endoprosthesis. Our results successfully demonstrated the feasibility of implanting a fully skin-covered rigid foot-ankle endoprosthesis to replace the lost tibia-foot segment of the lower limb. Concerns include the fibrotic capsule which could limit the range of motion of jointed endoprostheses. Future studies include testing of endoprosthetics, as well as materials and pharmacologic agents that may suppress fibrous encapsulation.

The use of visible light spectroscopy to measure tissue oxygenation in free flap reconstruction.

The loss of a free flap is a feared complication for both the surgeon and the patient. Early recognition of vascular compromise has been shown to provide the best chance for flap salvage. The ideal monitoring technique for perioperative free flap ischemia would be noninvasive, continuous, and reliable. Visible light spectroscopy (VLS) was evaluated as a new method for predicting ischemia in microvascular cutaneous soft tissue free flaps. In an Institutional Review Board-approved prospective trial, 12 patients were monitored after free flap reconstructions. The tissue hemoglobin oxygen saturation (StO (2)) and total hemoglobin concentration (THB) of 12 flaps were continuously monitored using VLS for 72 hours postoperatively. Out of these 12 flaps 11 were transplanted successfully and 1 flap loss occurred. The StO (2 )was 48.99% and the THB was 46.74% for the 12 flaps. There was no significant difference in these values among the flaps. For the single flap loss, the device accurately reflected the ischemic drop in StO (2) indicating drastic tissue ischemia at 6 hours postoperatively before the disappearance of implantable Doppler signals or clinical signs of flap compromise. VLS, a continuous, noninvasive, and localized method to monitor oxygenation, appeared to predict early ischemic complications after free flap reconstruction.

Fully Implanted Prostheses for Musculoskeletal Limb Reconstruction After Amputation: An In Vivo Feasibility Study.

Previous prostheses for replacing a missing limb following amputation must be worn externally on the body. This limits the extent to which prostheses could physically interface with biological tissues, such as muscles, to enhance functional recovery. The objectives of our study were to (1) test the feasibility of implanting a limb prosthesis, or endoprosthesis, entirely within living skin at the distal end of a residual limb, and (2) identify effective surgical and post-surgical care approaches for implanting endoprostheses in a rabbit model of hindlimb amputation. We iteratively designed, fabricated, and implanted unjointed endoprosthesis prototypes in six New Zealand White rabbits following amputation. In the first three rabbits, the skin failed to heal due to ishemia and dehiscence along the sutured incision. The skin of the final three subsequent rabbits successfully healed over the endoprotheses. Factors that contributed to successful outcomes included modifying the surgical incision to preserve vasculature; increasing the radii size on the endoprostheses to reduce skin stress; collecting radiographs pre-surgery to match the bone pin size to the medullary canal size; and ensuring post-operative bandage integrity. These results will support future work to test jointed endoprostheses that can be attached to muscles.

Continuous and Real-Time In Vivo Autobioluminescent Imaging in a Mouse Model.

In vivo small animal bioluminescent imaging has become an indispensable technique for interrogating the localization, health, and functionality of implanted cells within the complex environment of a living organism. However, this task can be daunting for even the most experienced researchers because it requires multiple animal handling steps and produces differential output signal characteristics in response to a number of experimental design variables. The recent emergence of autobioluminescent cells, which autonomously and continuously produce bioluminescent output signals without external stimulation, has the potential to simplify this process, reduce variability by removing human-induced error, and improve animal welfare by reducing the number of required needlesticks per procedure. This protocol details the implantation and imaging of autobioluminescent cells within a mouse model to demonstrate how cells implanted from a single injection can be imaged repeatedly across any post-implantation timescale without the need for further human-animal interaction or signal activation steps. This approach provides a facile means to continuously monitor implanted cellular output signals in real-time for extended time periods.

Functionalized Graphene Nanoparticles Induce Human Mesenchymal Stem Cells to Express Distinct Extracellular Matrix Proteins Mediating Osteogenesis.

PURPOSE: The extracellular matrix (ECM) labyrinthine network secreted by mesenchymal stem cells (MSCs) provides a microenvironment that enhances cell adherence, proliferation, viability, and differentiation. The potential of graphene-based nanomaterials to mimic a tissue-specific ECM has been recognized in designing bone tissue engineering scaffolds. In this study, we investigated the expression of specific ECM proteins when human fat-derived adult MSCs adhered and underwent osteogenic differentiation in the presence of functionalized graphene nanoparticles. METHODS: Graphene nanoparticles with 6-10% oxygen content were prepared and characterized by XPS, FTIR, AFM and Raman spectroscopy. Calcein-am and crystal violet staining were performed to evaluate viability and proliferation of human fat-derived MSCs on graphene nanoparticles. Alizarin red staining and quantitation were used to determine the effect of graphene nanoparticles on osteogenic differentiation. Finally, immunofluorescence assays were used to investigate the expression of ECM proteins during cell adhesion and osteogenic differentiation. RESULTS: Our data show that in the presence of graphene, MSCs express specific integrin heterodimers and exhibit a distinct pattern of the corresponding bone-specific ECM proteins, primarily fibronectin, collagen I and vitronectin. Furthermore, MSCs undergo osteogenic differentiation spontaneously without any chemical induction, suggesting that the physicochemical properties of graphene nanoparticles might trigger the expression of bone-specific ECM. CONCLUSION: Understanding the cell-graphene interactions resulting in an osteogenic niche for MSCs will significantly improve the application of graphene nanoparticles in bone repair and regeneration.

Human Fat-Derived Mesenchymal Stem Cells Xenogenically Implanted in a Rat Model Show Enhanced New Bone Formation in Maxillary Alveolar Tooth Defects.

BACKGROUND: Due to restorative concerns, bone regenerative therapies have garnered much attention in the field of human oral/maxillofacial surgery. Current treatments using autologous and allogenic bone grafts suffer from inherent challenges, hence the ideal bone replacement therapy is yet to be found. Establishing a model by which MSCs can be placed in a clinically acceptable bone defect to promote bone healing will prove valuable to oral/maxillofacial surgeons. METHODS: Human adipose tissue-derived MSCs were seeded onto Gelfoam® and their viability, proliferation, and osteogenic differentiation was evaluated in vitro. Subsequently, the construct was implanted in a rat maxillary alveolar bone defect to assess in vivo bone healing and regeneration. RESULTS: Human MSCs were adhered, proliferated, and uniformly distributed, and underwent osteogenic differentiation on Gelfoam®, comparable with the tissue culture surface. Data confirmed that Gelfoam® could be used as a scaffold for cell attachment and a delivery vehicle to implant MSCs in vivo. Histomorphometric analyses of bones harvested from rats treated with hMSCs showed statistically significant increase in collagen/early bone formation, with cells positive for osteogenic and angiogenic markers in the defect site. This pattern was visible as early as 4 weeks post treatment. CONCLUSIONS: Xenogenically implanted human MSCs have the potential to heal an alveolar tooth defect in rats. Gelfoam®, a commonly used clinical biomaterial, can serve as a scaffold to deliver and maintain MSCs to the defect site. Translating this strategy to preclinical animal models provides hope for bone tissue engineering.

Biometric Data Comparison Between Lewis and Sprague Dawley Rats.

Introduction: Pressure mapping systems are often used for indirect assessment of kinematic gait parameter differences after repair of critical peripheral nerve defects in small animal models. However, there does not appear to be any literature that studies the differences in normal gait pattern of Sprague Dawley rats compared to Lewis rats using a Tekscan VH4 pressure mat system. The purpose of this study is to assess the gait profile of Lewis and Sprague Dawley rats generated by Tekscan's VH4 system to detect similarities and/or differences in gait parameters involving both force and temporal variables. Materials and Methods: The gait profile of 14 Lewis and 14 Sprague Dawley rats was recorded using a Tekscan VH4 pressure map system with two successful walks per animal and gait parameter data was normalized for mean variance between the two rodent strains. Results: The results showed that temporal and normalized force parameters were not significantly different between the two types of rats. Maximum force, contact area, stride length, and adjusted pressure variables were significantly different between the two strains, likely attributed to the body size and weight differential between the strains. Variation in some of these parameters were considered due to differences in overall body size between the two strains, variations in gait kinematics between individual rodent subjects, and the limitations of the current experimental design. Conclusion: For future in vivo models, either Sprague Dawley or Lewis rat strains would be acceptable animal models when comparing base-line gait profiles using the Tekscan VH4 pressure map system when assessing critical defect repairs of peripheral nerves.

Functionalized gold nanorod nanocomposite system to modulate differentiation of human mesenchymal stem cells into neural-like progenitors.

A 2D multifunctional nanocomposite system of gold nanorods (AuNRs) was developed. Gold nanorods were functionalized via polyethylene glycol with a terminal amine, and, were characterized using transmission and scanning electron microscopy, ultra violet-visible and X-ray photoelectron spectroscopy, and Zeta-potential. The system was cytocompatible to and maintained the integrity of Schwann cells. The neurogenic potential of adipose tissue - derived human mesenchymal stem cells (hMSCs) was evaluated in vitro. The expression pattern and localization of Vimentin confirmed the mesenchymal origin of cells and tracked morphological changes during differentiation. The expression patterns of S100ß and glial fibrillary acidic protein (GFAP), were used as indicator for neural differentiation. Results suggested that this process was enhanced when the cells were seeded on the AuNRs compared to the tissue-culture surface. The present study indicates that the design and the surface properties of the AuNRs enhances neural differentiation of hMSCs and hence, would be beneficial for neural tissue engineering scaffolds.

Prior alcohol use enhances vulnerability to compulsive cocaine self-administration by promoting degradation of HDAC4 and HDAC5.

Addiction to cocaine is commonly preceded by experiences with legal or decriminalized drugs, such as alcohol, nicotine, and marijuana. The biological mechanisms by which these gateway drugs contribute to cocaine addiction are only beginning to be understood. We report that in the rat, prior alcohol consumption results in enhanced addiction-like behavior to cocaine, including continued cocaine use despite aversive consequences. Conversely, prior cocaine use has no effect on alcohol preference. Long-term, but not short-term, alcohol consumption promotes proteasome-mediated degradation of the nuclear histone deacetylases HDAC4 and HDAC5 in the nucleus accumbens, a brain region critical for reward-based memory. Decreased nuclear HDAC activity results in global H3 acetylation, creating a permissive environment for cocaine-induced gene expression. We also find that selective degradation of HDAC4 and HDAC5, facilitated by the class II-specific HDAC inhibitor MC1568, enhances compulsive cocaine self-administration. These results parallel our previously reported findings that the gateway drug nicotine enhances the behavioral effects of cocaine via HDAC inhibition. Together, our findings suggest a shared mechanism of action for the gateway drugs alcohol and nicotine, and reveal a novel mechanism by which environmental factors may alter the epigenetic landscape of the reward system to increase vulnerability to cocaine addiction.

Standardization of a novel blood-sampling method through the jugular vein for use in the quantified [14C] 2-deoxyglucose method.

In the traditional [14C] deoxyglucose (2DG) method for the measurement of local cerebral glucose utilization (LCGU), blood samples are collected from the femoral artery. However, the placement of a femoral catheter can affect locomotor activity of the animal. We wanted to develop a new technique for blood sampling that would not interfere with the ongoing behavior. Therefore, the present report establishes a method of collecting blood samples for the 2DG method through the jugular vein. To calibrate this method, catheters were inserted in both the femoral artery and jugular vein of adult male Sprague Dawley rats. The next day, rats were injected with 2DG (125 microCi/kg) through the jugular vein. To quantify 14C in plasma, the standard method of blood collection was used for the femoral artery while syringes were used to extract blood samples from the jugular vein. We calculated the integrated specific activity of the plasma and final tissue 2DG concentrations based on Sokoloff's original equation using blood samples derived from both vessels. LCGU determined in selected brain regions was equivalent using both sampling methods. In conclusion, sampling from the jugular vein is appropriate for the quantified 2DG method and does not disrupt locomotor activity of the rat.