Inflammatory status of transmigrating primary rat monocytes in a novel perfusion model simulating blood flow

Pump-Less Platform Enables Long-Term Recirculating Perfusion of 3D Printed Tubular Tissues

The direction and pattern of fluid flow affect vascular structure and function, in which vessel-lining endothelial cells exhibit variable cellular morphologies and vessel remodeling by mechanosensing. To recapitulate this microenvironment, some approaches have been reported to successfully apply unidirectional flow on endothelial cells in organ-on-a-chip systems. However, these platforms encounter drawbacks such as the dependency on pumps or confinement to closed microfluidic channels. These constraints impede their synergy with advanced biofabrication techniques like 3D bioprinting, thereby curtailing the potential to introduce greater complexity into engineered tissues. Herein, a pumpless recirculating platform (UniPlate) that enables unidirectional media recirculation through 3D printed tubular tissues, is demonstrated.The device is made of polystyrene via injection molding in combination with 3D printed sacrifical gelatin templates. Tubular blood vessels with unidirectional perfusion are firstly engineered. Then the design is expanded to incorporate duo-recirculating flow for culturing vascularized renal proximal tubules with glucose reabsorption function. In addition to media recirculation, human monocyte recirculation in engineered blood vessels is also demonstrated for over 24 h, with minimal loss of cells, cell viability, and inflammatory activation. UniPlate can be a valuable tool to more precisely control the cellular microenvironment of organ-on-a-chip systems for drug discovery.

Involvement of tumor necrosis factor-α, interferon gamma-γ, and interleukins 1β, 6, and 10 in immunosuppression due to long-term exposure to five common food preservatives in rats

BACKGROUND/AIMS

Food preservatives are abundant in many products in the human environment. However, little is known about the impact of many food preservatives on the immune system and the immune related genes. Hence, this study aimed to evaluate the effects of five widespread food preservatives, including butylated hydroxyanisole (BHA), potassium sorbate (PS), sodium benzoate (SB), boric acid (BA), and calcium propionate (CP), on haemato-immune functions.

METHOD

Sixty Sprague-Dawley rats were assigned to groups orally administered water (control), BHA (0.09 mg/kg), PS (4.5 mg/kg), SB (0.9 mg/kg), BA (0.16 mg/kg) or CP (0.18 mg/kg) for 90 consecutive days. Leukogram and erythrogram profiles were assessed. Nitric oxide and immunoglobulin levels together with phagocytic and lysozyme activities were estimated. Histologic examinations and histomorphometric analysis of splenic tissues were performed. Variations in the mRNA expression levels of tumour necrosis factor alpha (TNF-α), interferon gamma (IFNγ), interleukin (IL)-1β, IL-6, and IL-10 were assessed.

RESULTS

Anemic conditions, thrombocytopenia, leucocytopaenia simultaneous with lymphocytopaenia, monocytopenia, and esinopenia have been obvious following long term exposure to the tested food additives. Prominent exhaustion was noted in immunoglobulin and NO levels and in lysozyme and phagocytic activities. IFNγ, TNF-α, IL-1β, IL-6, and IL-10 were obviously upregulated in the groups exposed to food preservatives.

CONCLUSION

These results confirmed that continued exposure to high levels of BHA, PS, SB, BA, and CP has haematotoxic and immunotoxic effects. Furthermore, these adverse effects are mediated by cytokine production.

Towards a Physiological Scale of Vocal Fold Agent-Based Models of Surgical Injury and Repair: Sensitivity Analysis, Calibration and Verification

Agent based models (ABM) were developed to numerically simulate the biological response to surgical vocal fold injury and repair at the physiological level. This study aimed to improve the representation of existing ABM through a combination of empirical and computational experiments. Empirical data of vocal fold cell populations including neutrophils, macrophages and fibroblasts were obtained using flow cytometry up to four weeks following surgical injury. Random Forests were used as a sensitivity analysis method to identify model parameters that were most influential to ABM outputs. Statistical Parameter Optimization Tool for Python was used to calibrate those parameter values to match the ABM-simulation data with the corresponding empirical data from Day 1 to Day 5 following surgery. Model performance was evaluated by verifying if the empirical data fell within the 95% confidence intervals of ABM outputs of cell quantities at Day 7, Week 2 and Week 4. For Day 7, all empirical data were within the ABM output ranges. The trends of ABM-simulated cell populations were also qualitatively comparable to those of the empirical data beyond Day 7. Exact values, however, fell outside of the 95% statistical confidence intervals. Parameters related to fibroblast proliferation were indicative to the ABM-simulation of fibroblast dynamics in final stages of wound healing.

Ibuprofen prevents progression of ataxia telangiectasia symptoms in ATM-deficient mice

BACKGROUND

Inflammation plays a critical role in accelerating the progression of neurodegenerative diseases, such as Alzheimer's disease (AD) and ataxia telangiectasia (A-T). In A-T mouse models, LPS-induced neuroinflammation advances the degenerative changes found in cerebellar Purkinje neurons both in vivo and in vitro. In the current study, we ask whether ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), can have the opposite effect and delay the symptoms of the disease.

METHODS

We tested the beneficial effects of ibuprofen in both in vitro and in vivo models. Conditioned medium from LPS stimulated primary microglia (LM) applied to cultures of dissociated cortical neurons leads to numerous degenerative changes. Pretreatment of the neurons with ibuprofen, however, blocked this damage. Systemic injection of LPS into either adult wild-type or adult Atm-/- mice produced an immune challenge that triggered profound behavioral, biochemical, and histological effects. We used a 2-week ibuprofen pretreatment regimen to investigate whether these LPS effects could be blocked. We also treated young presymptomatic Atm-/- mice to determine if ibuprofen could delay the appearance of symptoms.

RESULTS

Adding ibuprofen directly to neuronal cultures significantly reduced LM-induced degeneration. Curiously, adding ibuprofen to the microglia cultures before the LPS challenge had little effect, thus implying a direct effect of the NSAID on the neuronal cultures. In vivo administration of ibuprofen to Atm-/- animals before a systemic LPS immune challenge suppressed cytological damage. The ibuprofen effects were widespread as microglial activation, p38 phosphorylation, DNA damage, and neuronal cell cycle reentry were all reduced. Unfortunately, ibuprofen only slightly improved the LPS-induced behavioral deficits. Yet, while the behavioral symptoms could not be reversed once they were established in adult Atm-/- animals, administration of ibuprofen to young mutant pups prevented their symptoms from appearing.

CONCLUSION

Inflammatory processes impact the normal progression of A-T implying that modulation of the immune system can have therapeutic benefit for both the behavioral and cellular symptoms of this neurodegenerative disease.

Effects of the food additives sodium acid pyrophosphate, sodium acetate, and citric acid on hemato-immunological pathological biomarkers in rats: Relation to PPAR-α, PPAR-γ and tnfα signaling pathway

The food additives sodium acid pyrophosphate (SAPP), sodium acetate (SA), and citric acid (CA) were evaluated for their hemato-immunotoxic effects. Forty adult Sprague-Dawley rats were distributed into four groups and were orally administered water, SAPP (12.6 mg/kg), CA (180 mg/kg), or SA (13.5 mg /kg) daily for 90 days. Erythrogram and leukogram profiles were evaluated. The levels of lysozyme, nitric oxide, immunoglobulin, and phagocytic activity were measured. Histologic and immunohistochemical evaluations of splenic tissues were performed. Changes in the mRNA expression levels of peroxisome proliferator-activated receptor α and γ (PPAR-α and PPAR-γ), and tumor necrosis factor α (TNF-α) genes were assessed. A significant leukopenic condition was observed with SAPP, while CA induced marked leukocytosis, and SA showed a lymphocytosis condition. Both the innate and humoral parameters were significantly depressed. Various pathological lesions were observed, including diffuse hyperplasia of the red pulp, depletion of the white pulp, and capsular and parenchymal fibrosis. A marked decrease in CD3 T-lymphocyte and CD20 B-lymphocyte immunolabeling in rats treated with SAPP and SA was evident. Marked downregulation of PPAR-α and PPAR-γ together with upregulation of TNF-α was recorded. These results indicate that high doses of SAPP, SA and CA exert hematotoxic and immunotoxic effects with long-term exposure.

On-chip immune cell activation and subsequent time-resolved magnetic bead-based cytokine detection

Cytokine profiling and immunophenotyping offer great potential for understanding many disease mechanisms, personalized diagnosis, and immunotherapy. Here, we demonstrate a time-resolved detection of cytokine from a single cell cluster using an in situ magnetic immune assay. An array of triple-layered microfluidic chambers was fabricated to enable simultaneous cell culture under perfusion flow and detection of the induced cytokines at multiple time-points. Each culture chamber comprises three fluidic compartments which are dedicated to, cell culture, perfusion and immunoassay. The three compartments are separated by porous membranes, which allow the diffusion of fresh nutrient from the perfusion compartment into the cell culture compartment and cytokines secretion from the cell culture compartment into the immune assay compartment. This structure hence enables capturing the released cytokines without disturbing the cell culture and without minimizing benefit gain from perfusion. Functionalized magnetic beads were used as a solid phase carrier for cytokine capturing and quantification. The cytokines released from differential stimuli were quantified in situ in non-differentiated U937 monocytes and differentiated macrophages.

A Single 9-Colour Flow Cytometric Method to Characterise Major Leukocyte Populations in the Rat: Validation in a Model of LPS-Induced Pulmonary Inflammation

The rat is a commonly used model for immunological investigation. Yet basic research and characterisation of leukocyte populations and sub-sets lags far behind murine research, with inconsistency on reported leukocyte markers and their overlap. These shortcomings limit the opportunity for more complex and advanced rat immunology research. In this study, we developed a robust 9-colour flow-cytometric protocol to elucidate the major blood and tissue rat leukocyte populations, and validated it in a model of LPS-induced pulmonary inflammation. Blood and tissues (lung, BALF, spleen, liver, bone marrow) from naïve Sprague-Dawley rats were collected and analysed by flow cytometry (FCM). Rats were exposed to aerosolised saline or LPS (1 mg/mL), at 3 and 24 hrs thereafter blood, lung and BALF were collected and analysed using FCM and ELISA. Neutrophils, two monocyte subsets, NK Cells, B Cells, CD4+, CD8+ T Cells and alveolar macrophages can be identified simultaneously across different tissues using a 9-colour panel. Neutrophils and monocytes can be distinguished based upon differential expression of CD43 and His48. Neutrophils and CD43Lo/His48Hi monocyte-macrophages are elevated in the lung at 3 and 24 hrs during LPS-induced pulmonary inflammation. This validated method for leukocyte enumeration will offer a platform for greater consistency in future rat immunology and inflammation research.