Microfiltration method of removal of bacterial contaminants and their monitoring by nitric oxide and Limulus assays

Extracellular matrix inclusion in immunoisolating alginate-based microcapsules promotes longevity, reduces fibrosis, and supports function of islet allografts in vivo

Immunoisolation of pancreatic-islets in alginate-microcapsules is applied to treat diabetes. However, long-term islet function is limited, which might be due to damaged and lack of contact with pancreatic extracellular matrix (ECM) components. Herein we investigated the impact of collagen IV combined with laminin sequences, either RGD, LRE, or PDSGR, on graft-survival of microencapsulated bioluminescent islets in vivo. Collagen IV with RGD had the most pronounced effect. It enhanced after 8-week implantation in immune-incompetent mice the bioluminescence of allogeneic islets by 3.2-fold, oxygen consumption rate by 14.3-fold and glucose-induced insulin release by 9.6-fold. Transcriptomics demonstrated that ECM enhanced canonical pathways involving insulin-secretion and that it suppressed pathways related to inflammation and hypoxic stress. Also, 5.8-fold fewer capsules were affected by fibrosis. In a subsequent longevity study in immune-competent mice, microencapsulated allografts containing collagen IV and RGD had a 2.4-fold higher functionality in the first week after implantation and remained at least 2.1-fold higher during the study. Islets in microcapsules containing collagen IV and RGD survived 211 ± 24.1 days while controls survived 125 ± 19.7 days. Our findings provide in vivo evidence for the efficacy of supplementing immunoisolating devices with specific ECM components to enhance functionality and longevity of islet-grafts in vivo. STATEMENT OF SIGNIFICANCE: Limitations in duration of survival of immunoisolated pancreatic islet grafts is a major obstacle for application of the technology to treat diabetes. Accumulating evidence supports that incorporation of extracellular matrix (ECM) molecules in the capsules enhances longevity of pancreatic islets. After selection of the most efficacious laminin sequence in vitro, we show in vivo that inclusion of collagen IV and RGD in alginate-based microcapsules enhances survival, insulin secretion function, and mitochondrial function. It also suppresses fibrosis by lowering proinflammatory cytokines secretion. Moreover, transcriptomic analysis shows that ECM-inclusion promotes insulin-secretion related pathways and attenuates inflammation and hypoxic stress related pathways in islets. We show that inclusion of ECM in immunoisolating devices is a promising strategy to promote long-term survival of islet-grafts.

Gene Expression Changes Induced by Exposure of RAW 264.7 Macrophages to Particulate Matter of Air Pollution: The Role of Endotoxins

Despite the variable chemical and physical characteristics of particulate air pollutants, inflammation and oxidative stress have been identified as common mechanisms for cell damage and negative health influences. These effects are produced by organic components, especially by endotoxins. This study analyzed the gene expression profile after exposure of RAW 264.7 cells to the standard particulate matter (PM) material, NIST1648a, and PM with a reduced organic matter content, LAp120, in comparison to the effects of lipopolysaccharide (LPS). The selected parameters of cell viability, cell cycle progression, and metabolic and inflammatory activity were also investigated. Both forms of PM negatively influenced the parameters of cell activity. These results were generally reflected in the gene expression profile. Only NIST1648a, excluding LAp120, contained endotoxins and showed small but statistically significant pro-inflammatory activity. However, the gene expression profiling revealed strong pro-inflammatory cell activation induced by NIST1648a that was close to the effects of LPS. Changes in gene expression triggered by LAp120 were relatively small. The observed differences in the effects of NIST1648a and LAp120 were related to the content of organic matter in which bacterial endotoxins play an important role. However, other organic compounds and their interactions with other PM components also appear to be of significant importance.

Detection of contaminants in water supply: A review on state-of-the-art monitoring technologies and their applications

Water monitoring technologies are widely used for contaminants detection in wide variety of water ecology applications such as water treatment plant and water distribution system. A tremendous amount of research has been conducted over the past decades to develop robust and efficient techniques of contaminants detection with minimum operating cost and energy. Recent developments in spectroscopic techniques and biosensor approach have improved the detection sensitivities, quantitatively and qualitatively. The availability of in-situ measurements and multiple detection analyses has expanded the water monitoring applications in various advanced techniques including successful establishment in hand-held sensing devices which improves portability in real-time basis for the detection of contaminant, such as microorganisms, pesticides, heavy metal ions, inorganic and organic components. This paper intends to review the developments in water quality monitoring technologies for the detection of biological and chemical contaminants in accordance with instrumental limitations. Particularly, this review focuses on the most recently developed techniques for water contaminant detection applications. Several recommendations and prospective views on the developments in water quality assessments will also be included.

A Technology Platform to Test the Efficacy of Purification of Alginate

Alginates are widely used in tissue engineering technologies, e.g., in cell encapsulation, in drug delivery and various immobilization procedures. The success rates of these studies are highly variable due to different degrees of tissue response. A cause for this variation in success is, among other factors, its content of inflammatory components. There is an urgent need for a technology to test the inflammatory capacity of alginates. Recently, it has been shown that pathogen-associated molecular patterns (PAMPs) in alginate are potent immunostimulatories. In this article, we present the design and evaluation of a technology platform to assess (i) the immunostimulatory capacity of alginate or its contaminants, (ii) where in the purification process PAMPs are removed, and (iii) which Toll-like receptors (TLRs) and ligands are involved. A THP1 cell-line expressing pattern recognition receptors (PRRs) and the co-signaling molecules CD14 and MD2 was used to assess immune activation of alginates during the different steps of purification of alginate. To determine if this activation was mediated by TLRs, a THP1-defMyD88 cell-line was applied. This cell-line possesses a non-functional MyD88 coupling protein, necessary for activating NF-κB via TLRs. To identify the specific TLRs being activated by the PAMPs, we use different human embryonic kidney (HEK) cell-line that expresses only one specific TLR. Finally, specific enzyme-linked immunosorbent assays (ELISAs) were applied to identify the specific PAMP. By applying this three-step procedure, we can screen alginate in a manner, which is both labor and cost efficient. The efficacy of the platform was evaluated with an alginate that did not pass our quality control. We demonstrate that this alginate was immunostimulatory, even after purification due to reintroduction of the TLR5 activating flagellin. In addition, we tested two commercially available purified alginates. Our experiments show that these commercial alginates contained peptidoglycan, lipoteichoic acid, flagellin, and even lipopolysaccharides (LPS). The platform presented here can be used to evaluate the efficacy of purification procedures in removing PAMPs from alginates in a cost-efficient manner.

PEP-1-PON1 protein regulates inflammatory response in raw 264.7 macrophages and ameliorates inflammation in a TPA-induced animal model

Paraoxonase 1 (PON1) is an antioxidant enzyme which plays a central role in various diseases. However, the mechanism and function of PON1 protein in inflammation are poorly understood. Since PON1 protein alone cannot be delivered into cells, we generated a cell permeable PEP-1-PON1 protein using protein transduction domains, and examined whether it can protect against cell death in lipopolysaccharide (LPS) or hydrogen peroxide (H₂O₂)-treated Raw 264.7 cells as well as mice with 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced skin inflammation. We demonstrated that PEP-1-PON1 protein transduced into Raw 264.7 cells and markedly protected against LPS or H₂O₂-induced cell death by inhibiting cellular reactive oxygen species (ROS) levels, the inflammatory mediator’s expression, activation of mitogen-activated protein kinases (MAPKs) and cellular apoptosis. Furthermore, topically applied PEP-1-PON1 protein ameliorates TPA-treated mice skin inflammation via a reduction of inflammatory response. Our results indicate that PEP-1-PON1 protein plays a key role in inflammation and oxidative stress in vitro and in vivo. Therefore, we suggest that PEP-1-PON1 protein may provide a potential protein therapy against oxidative stress and inflammation.