Tackling Ischemic Reperfusion Injury With the Aid of Stem Cells and Tissue Engineering

A review: Carrier-based hydrogels containing bioactive molecules and stem cells for ischemic stroke therapy

Ischemic stroke (IS), a cerebrovascular disease, is the leading cause of physical disability and death worldwide. Tissue plasminogen activator (tPA) and thrombectomy are limited by a narrow therapeutic time window. Although strategies such as drug therapies and cellular therapies have been used in preclinical trials, some important issues in clinical translation have not been addressed: low stem cell survival and drug delivery limited by the blood-brain barrier (BBB). Among the therapeutic options currently sought, carrier-based hydrogels hold great promise for the repair and regeneration of neural tissue in the treatment of ischemic stroke. The advantage lies in the ability to deliver drugs and cells to designated parts of the brain in an injectable manner to enhance therapeutic efficacy. Here, this article provides an overview of the use of carrier-based hydrogels in ischemic stroke therapy and focuses on the use of hydrogel scaffolds containing bioactive molecules and stem cells. In addition to this, we provide a more in-depth summary of the composition, physicochemical properties and physiological functions of the materials themselves. Finally, we also outline the prospects and challenges for clinical translation of hydrogel therapy for IS.

USP38 protects intestinal epithelial cells from ischemia/reperfusion injury by stabilizing BIRC5

Background

Intestinal ischemia/reperfusion (II/R) is a severe condition with high mortality and limited treatment options. Extracellular vesicles that are derived from bone marrow mesenchymal stem cells (BM-MSC-EVs) exhibit therapeutic potential in alleviating II/R injury. However, the mechanism by which BM-MSC-EVs fulfill this function requires further characterization. The ubiquitin-proteasome system plays an essential role in II/R, but the functions of individual ubiquitination regulators such as ubiquitin-specific proteases (USPs) in this process remain incompletely understood.

Methods

An II/R cellular model was established by using IEC-6 intestinal epithelial cells with oxygen-glucose deprivation/reperfusion (OGD/R) treatment. The expression of USPs was evaluated by using quantitative polymerase chain reaction and Western blot. The role of USP38 on the viability, apoptosis, migration, and reactive oxygen species (ROS) levels in OGD/R-treated IEC-6 cells were measured by using CCK-8, Annexin V/PI staining, transwell assay, and 2',7'-dichlorofluorescin diacetate (DCFDA) staining, respectively. The interaction between USP38 and BIRC5 was explored by using co-immunoprecipitation (Co-IP) and the ubiquitination level and stability of BIRC5 were examined by using Western blot. USP38-overexpressing BM-MSC-EVs were produced to treat OGD/R-treated IEC-6 cells.

Results

USP38 expression was significantly downregulated in OGD/R-treated IEC-6 cells. Incubation of these cells with BM-MSC-EVs substantially elevated the USP38 expression, resulting in improved viability, reduced apoptosis, enhanced migration, and decreased ROS levels. Furthermore, overexpression of USP38 in BM-MSC-EVs further enhanced their protective effect on OGD/R-treated IEC-6 cells. At the molecular level, USP38 interacts with and stabilizes BIRC5 by decreasing its ubiquitination. Knock-down of BIRC5 abolished the protective effect of excessive USP38 on OGD/R-treated IEC-6 cells.

Conclusion

USP38 protects intestinal epithelial cells from I/R injury by enhancing the stability of BIRC5.

HPLC-PDA and in vivo anti-inflammatory potential of isorhamnetin-3-O-β-D-glucoside from Zygophyllum simplex L

ETHNOPHARMACOLOGICAL RELEVANCE

Inflammation is a biological process in response to injury, resulting in altered blood flow, increased vascular permeability, tissue destruction, and the production of reactive oxygen species (ROS) and inflammatory mediators. Zygophyllum simplex L., a medicinal plant traditionally used in the Arabian Peninsula for inflammatory disorders, has demonstrated promising in vitro anti-inflammatory activity due to its phenolic content. Additionally, the ethyl acetate fraction has exhibited notable in vivo anti-inflammatory effects.

STUDY OBJECTIVE

This research aimed to evaluate the in vivo anti-inflammatory effects of a Z. simplex plant extract and its principal ethyl acetate isolate, isorhamnetin-3-O-β-D-glucoside (Isor-3-Glu). The study seeks to develop a straightforward and robust HPLC method for quantifying Isor-3-Glu within the total methanolic extract of Z. simplex.

MATERIALS AND METHODS

The total methanol extract of Z. simplex was successively partitioned with a variety of organic solvents and the ethyl acetate fraction was used to isolate Isor-3-Glu on a Sephadex LH-20 column. The in vivo anti-inflammatory activity was investigated using carrageenan-triggered inflammation in rats. Histological features and immunohistochemical expression of cyclooxygenase-2 (COX-2) and tumor necrosis factor-alpha (TNF-α) were analyzed, and the levels of interleukins (IL-1β and IL-6) as well as prostaglandin E2 (PGE2) of the paw tissues were examined by qRT-PCR and ELISA, respectively. Quantification of Isor-3-Glu was achieved using an HPLC-PDA method.

RESULTS

Isor-3-Glu considerably (p < 0.05) lowered the weight of the paw edema. The histological abnormalities were improved, and the percentage of the COX-2 and TNF-α immunoreactive cells substantially decreased in the Isor-3-Glu-treated group in comparison with the positive control and Z. simplex extract group. Isor-3-Glu significantly ameliorated PGE2, IL-1β, and IL-6 levels. A straightforward and dependable HPLC technique was established for quantifying Isor-3-Glu in the total extract. The proposed methodology effectively determined Isor-3-Glu in less than 5 min. The calibration curve exhibited a linear relationship over the concentration range of 1.0-40.0 μg/mL, with a correlation coefficient (r) ≥ 0.9995. The developed method demonstrated a high level of sensitivity, with a detection limit as low as 0.139 μg/mL. The concentration of Isor-3-Glu in the total extract of Z. simplex was determined to be 0.05% w/w of dry extract.

CONCLUSION

Isor-3-Glu could be considered a promising anti-inflammatory compound that necessitates future clinical research. Isor-3-Glu was accurately quantified using a meticulously developed and optimized HPLC-PDA technique.

Mechanistic Insights into Alternative Gene Splicing in Oxidative Stress and Tissue Injury

Significance: Oxidative stress (OS) and inflammation are inducers of tissue injury. Alternative splicing (AS) is an essential regulatory step for diversifying the eukaryotic proteome. Human diseases link AS to OS; however, the underlying mechanisms must be better understood. Recent Advances: Genome‑wide profiling studies identify new differentially expressed genes induced by OS-dependent ischemia/reperfusion injury. Overexpression of RNA-binding protein RBFOX1 protects against inflammation. Hypoxia-inducible factor-1α directs polypyrimidine tract binding protein 1 to regulate mouse carcinoembryonic antigen-related cell adhesion molecule 1 (Ceacam1) AS under OS conditions. Heterogeneous nuclear ribonucleoprotein L variant 1 contains an RGG/RG motif that coordinates with transcription factors to influence human CEACAM1 AS. Hypoxia intervention involving short interfering RNAs directed to long-noncoding RNA 260 polarizes M2 macrophages toward an anti-inflammatory phenotype and alleviates OS by inhibiting IL-28RA gene AS. Critical Issues: Protective mechanisms that eliminate reactive oxygen species (ROS) are important for resolving imbalances that lead to chronic inflammation. Defects in AS can cause ROS generation, cell death regulation, and the activation of innate and adaptive immune factors. We propose that AS pathways link redox regulation to the activation or suppression of the inflammatory response during cellular stress. Future Directions: Emergent studies using molecule-mediated RNA splicing are being conducted to exploit the immunogenicity of AS protein products. Deciphering the mechanisms that connect misspliced OS and pathologies should remain a priority. Controlled release of RNA directly into cells with clinical applications is needed as the demand for innovative nucleic acid delivery systems continues to be demonstrated.

Smart Dressings and Their Applications in Chronic Wound Management

During chronic wound healing, the inflammatory phase can endure for extended periods, heavily impeding or halting the process. Regular inspections and dressing changes are crucial. Modern dressings like hydrogels, hydrocolloids, and foam provide protection and an optimal healing environment. However, they have limitations in offering real-time wound bed status and healing rate. Evaluation relies heavily on direct observation, and passive dressings fail to identify subtle healing differences, preventing adaptive adjustments in biological factors and drug concentrations. In recent years, the clinical field recognizes the value of integrating intelligent diagnostic tools into wound dressings. By monitoring biomarkers linked to chronic wounds' inflammatory state, real-time data can be captured, reducing medical interventions and enabling more effective treatment plans. This fosters innovation in chronic wound care. Researchers have developed smart dressings with sensing, active drug delivery, and self-adjustment capabilities. These dressings detect inflammatory markers like temperature, pH, and oxygen content, enhancing drug bioavailability on the wound surface. As wound healing technology evolves, these smart dressings hold immense potential in chronic wound care and treatment. This comprehensive review updates our understanding on the role and mechanism of action of the smart dressings in chronic refractory wounds by summarizing and discussing the latest research progresses, including the intelligent monitoring of wound oxygen content, temperature, humidity, pH, infection, and enzyme kinetics; intelligent drug delivery triggered by temperature, pH, near-infrared, and electricity; as well as the intelligent self-adjustment of pressure and shape. The review also delves into the constraints and future perspectives of smart dressings in clinical settings, thereby advancing the development of smart wound dressings for chronic wound healing and their practical application in clinical practice.

Effect of peripheral blood mononuclear cells on ischemia-reperfusion injury of sciatic nerve of adult male albino rat: histological, immunohistochemical, and ultrastructural study

Ischemia/reperfusion (I/R) injury of sciatic nerve is a serious condition that results in nerve fiber degeneration, and reperfusion causes oxidative injury. Peripheral blood mononuclear cells (PBMNCs) have neuroregenerative power. This study was carried out to evaluate the potential ameliorative effect of PBMNCs on changes induced by I/R injury of the sciatic nerve. Fifty adult male albino rats were divided into donor and experimental groups that were subdivided into four groups: group I (control group), group II received 50 µL PBNMCs once intravenously via the tail vein, group III rubber tourniquet was placed around their Rt hind limb root for 2 hours to cause ischemia, group IV was subjected to limb ischemia as group III, then they were injected with 50 ul PBMNCs as group II before reperfusion. I/R injury showed disorganization of nerve fascicles with wide spaces in between nerve fibers. The mean area of collagen fibers, iNOS immunoexpression, and number of GFAP-positive Schwann cells of myelinated fibers showed a highly significant increase, while a highly significant reduction in the G-ratio and neurofilament immunoexpression was observed. Myelin splitting, invagination, evagination, and myelin figures were detected. PBMNC-treated group showed a marked improvement that was confirmed by histological, immunohistochemical, and ultrastructural findings.

Establishing Salvia miltiorrhiza-Derived Exosome-like Nanoparticles and Elucidating Their Role in Angiogenesis

Exosomes are multifunctional, cell-derived nanoscale membrane vesicles. Exosomes derived from certain mammalian cells have been developed as angiogenesis promoters for the treatment of myocardial ischemia-reperfusion injury, as they possess the capability to enhance endothelial cell proliferation, migration, and angiogenesis. However, the low yield of exosomes derived from mammalian cells limits their clinical applications. Therefore, we chose to extract exosome-like nanoparticles from the traditional Chinese medicine Salvia miltiorrhiza, which has been shown to promote angiogenesis. Salvia miltiorrhiza-derived exosome-like nanoparticles offer advantages, such as being economical, easily obtainable, and high-yielding, and have an ideal particle size, Zeta potential, exosome-like morphology, and stability. Salvia miltiorrhiza-derived exosome-like nanoparticles can enhance the cell viability of Human Umbilical Vein Endothelial Cells and can promote cell migration and improve the neovascularization of the cardiac tissues of myocardial ischemia-reperfusion injury, indicating their potential as angiogenesis promoters for the treatment of myocardial ischemia-reperfusion injury.

Comprehensive Overview of Innovative Strategies in Preventing Renal Ischemia-reperfusion Injury: Insights from Bibliometric and In silico Analyses

BACKGROUND

Ischemia-reperfusion Injury (IRI) is a complex pathophysiological process with severe consequences, including irreversible loss of renal function. Various intraoperative prevention methods have been proposed to mitigate the harmful effects of warm ischemia and kidney reperfusion.

AIM

This comprehensive analysis provides an overview of pharmacological agents and intraoperative methods for preventing and treating renal IRI.

METHODS

Our analysis revealed that eplerenone exhibited the highest binding affinity to crucial targets, including Aldehyde Dehydrogenase (AD), Estrogen Receptor (ER), Klotho protein, Mineralocorticoid Receptor (MR), and Toll-like Receptor 4 (TLR4). This finding indicates eplerenone's potential as a potent preventive agent against IRI, surpassing other available therapeutics like Benzodioxole, Hydrocortisone, Indoles, Nicotinamide adenine dinucleotide, and Niacinamide. In preventing kidney IRI, our comprehensive analysis emphasizes the significance of eplerenone due to its strong binding affinity to key targets involved in the pathogenesis of IRI.

RESULTS

This finding positions eplerenone as a promising candidate for further clinical investigation and consideration for future clinical practice.

CONCLUSION

The insights provided in this analysis will assist clinicians and researchers in selecting effective preventive approaches for renal IRI in surgical settings, potentially improving patient outcomes.

Engineering Organ-on-a-Chip Systems for Vascular Diseases

Vascular diseases, such as atherosclerosis and thrombosis, are major causes of morbidity and mortality worldwide. Traditional in vitro models for studying vascular diseases have limitations, as they do not fully recapitulate the complexity of the in vivo microenvironment. Organ-on-a-chip systems have emerged as a promising approach for modeling vascular diseases by incorporating multiple cell types, mechanical and biochemical cues, and fluid flow in a microscale platform. This review provides an overview of recent advancements in engineering organ-on-a-chip systems for modeling vascular diseases, including the use of microfluidic channels, ECM (extracellular matrix) scaffolds, and patient-specific cells. We also discuss the limitations and future perspectives of organ-on-a-chip for modeling vascular diseases.

Impact of hypoxia and reoxygenation on the extra/intracellular metabolome and on transporter expression in a human kidney proximal tubular cell line

INTRODUCTION

Ischemia-reperfusion injury (IRI) induces several perturbations that alter immediate kidney graft function after transplantation and may affect long-term graft outcomes. Given the IRI-dependent metabolic disturbances previously reported, we hypothesized that proximal transporters handling endo/exogenous substrates may be victims of such lesions.

OBJECTIVES

This study aimed to determine the impact of hypoxia/reoxygenation on the human proximal transport system through two semi-targeted omics analyses.

METHODS

Human proximal tubular cells were cultured in hypoxia (6 or 24 h), each followed by 2, 24 or 48-h reoxygenation. We investigated the transcriptomic modulation of transporters. Using semi-targeted LC-MS/MS profiling, we characterized the extra/intracellular metabolome. Statistical modelling was used to identify significant metabolic variations.

RESULTS

The expression profile of transporters was impacted during hypoxia (y + LAT1 and OCTN2), reoxygenation (MRP2, PEPT1/2, rBAT, and OATP4C1), or in both conditions (P-gp and GLUT1). The P-gp and GLUT1 transcripts increased (FC (fold change) = 2.93 and 4.11, respectively) after 2-h reoxygenation preceded by 24-h hypoxia. We observed a downregulation (FC = 0.42) of y+LAT1 after 24-h hypoxia, and of PEPT2 after 24-h hypoxia followed by 2-h reoxygenation (FC = 0.40). Metabolomics showed that hypoxia altered the energetic pathways. However, intracellular metabolic homeostasis and cellular exchanges were promptly restored after reoxygenation.

CONCLUSION

This study provides insight into the transcriptomic response of the tubular transporters to hypoxia/reoxygenation. No correlation was found between the expression of transporters and the metabolic variations observed. Given the complexity of studying the global tubular transport systems, we propose that further studies focus on targeted transporters.

New Insight on the Cytoprotective/Antioxidant Pathway Keap1/Nrf2/HO-1 Modulation by Ulva intestinalis Extract and Its Selenium Nanoparticles in Rats with Carrageenan-Induced Paw Edema

Currently, there is growing interest in exploring natural bioactive compounds with anti-inflammatory potential to overcome the side effects associated with the well-known synthetic chemicals. Algae are a rich source of bioactive molecules with numerous applications in medicine. Herein, the anti-inflammatory effect of Ulva intestinalis alone or selenium nanoparticles loaded with U. intestinalis (UISeNPs), after being fully characterized analytically, was investigated by a carrageenan-induced inflammation model. The pretreated groups with free U. intestinalis extract (III and IV) and the rats pretreated with UISeNPs (groups V and VI) showed significant increases in the gene expression of Keap1, with fold increases of 1.9, 2.27, 2.4, and 3.32, respectively. Similarly, a remarkable increase in the Nrf2 gene expression, with 2.09-, 2.36-, 2.59-, and 3.7-fold increases, was shown in the same groups, respectively. Additionally, the groups III, IV, V, and VI revealed a significantly increased HO-1 gene expression with a fold increase of 1.48, 1.61, 1.87, and 2.84, respectively. Thus, both U. intestinalis extract and the UISeNPs boost the expression of the cytoprotective/antioxidant pathway Keap1/Nrf2/HO-1, with the UISeNPs having the upper hand over the free extract. In conclusion, U. intestinalis and UISeNPs have proven promising anti-inflammatory activity through mediating different underlying mechanisms.

New therapeutic concepts against ischemia-reperfusion injury in organ transplantation

INTRODUCTION

Ischemia-reperfusion injury (IRI) involves a positive amplification feedback loop that stimulates innate immune-driven tissue damage associated with organ procurement from deceased donors and during transplantation surgery. As our appreciation of its basic immune mechanisms has improved in recent years, translating putative biomarkers into therapeutic interventions in clinical transplantation remains challenging.

AREAS COVERED

This review presents advances in translational/clinical studies targeting immune responses to reactive oxygen species in IRI-stressed solid organ transplants, especially livers. Here we focus on novel concepts to rejuvenate suboptimal donor organs and improve transplant function using pharmacologic and machine perfusion (MP) strategies. Cellular damage induced by cold ischemia/warm reperfusion and the latest mechanistic insights into the microenvironment's role that leads to reperfusion-induced sterile inflammation is critically discussed.

EXPERT OPINION

Efforts to improve clinical outcomes and increase the donor organ pool will depend on improving donor management and our better appreciation of the complex mechanisms encompassing organ IRI that govern the innate-adaptive immune interface triggered in the peritransplant period and subsequent allo-Ag challenge. Computational techniques and deep machine learning incorporating the vast cellular and molecular mechanisms will predict which peri-transplant signals and immune interactions are essential for improving access to the long-term function of life-saving transplants.

Anti-inflammatory potential of Penicillium brefeldianum endophytic fungus supported with phytochemical profiling

Various factors contribute to the development of the acute inflammation process, like the pro-inflammatory cytokines, certain enzymes as well as oxidative stress mediators. The anti-inflammatory potential of the endophytic fungus Penicillium brefeldianum was explored in carrageenan-induced inflammation in rats. After isolation of the fungus from Acalypha hispida leaves, it was identified by 18S rRNA gene sequencing. Then, its phytochemical profile was elucidated using LC-ESI-MS/MS technique. There was a remarkable decrease in the edema weight in the endophytic fungi-treated group (200 mg/kg). Also, this group had few inflammatory cells and thickened epidermis with underlying moderate collagenosis when stained with haematoxylin and eosin. Besides, immunostaining with monoclonal antibodies of cyclooxygenase-2 and tumor necrosis factor alpha showed a decrease in the positive immune cells in the endophytic fungi treated group (200 mg/kg) in relation to the positive control. Interestingly, the levels of the inflammatory as well as oxidative stress markers, including prostaglandin E2, nitric oxide, and malondialdehyde, which are hallmarks of the inflammatory process, considerably diminished (p < 0.05) in this group. qRT-PCR was utilised to elucidate the impact of the endophytic fungi treatment on the expression of interleukins (IL-1β and IL-6) genes, which decreased in comparison with the positive control group. Consequently, we can deduce that P. brefeldianum endophytic fungus has a promising anti-inflammatory potential and should be extensively studied on a broader range in the near future.

Ischemic Tolerance—A Way to Reduce the Extent of Ischemia–Reperfusion Damage

Individual tissues have significantly different resistance to ischemia–reperfusion damage. There is still no adequate treatment for the consequences of ischemia–reperfusion damage. By utilizing ischemic tolerance, it is possible to achieve a significant reduction in the extent of the cell damage due to ischemia–reperfusion injury. Since ischemia–reperfusion damage usually occurs unexpectedly, the use of preconditioning is extremely limited. In contrast, postconditioning has wider possibilities for use in practice. In both cases, the activation of ischemic tolerance can also be achieved by the application of sublethal stress on a remote organ. Despite very encouraging and successful results in animal experiments, the clinical results have been disappointing so far. To avoid the factors that prevent the activation of ischemic tolerance, the solution has been to use blood plasma containing tolerance effectors. This plasma is taken from healthy donors in which, after exposure to two sublethal stresses within 48 h, effectors of ischemic tolerance occur in the plasma. Application of this activated plasma to recipient animals after the end of lethal ischemia prevents cell death and significantly reduces the consequences of ischemia–reperfusion damage. Until there is a clear chemical identification of the end products of ischemic tolerance, the simplest way of enhancing ischemic tolerance will be the preparation of activated plasma from young healthy donors with the possibility of its immediate use in recipients during the initial treatment.

Fabrication of Celecoxib PVP Microparticles Stabilized by Gelucire 48/16 via Electrospraying for Enhanced Anti-Inflammatory Action

Electrospraying (ES) technology is considered an efficient micro/nanoparticle fabrication technique with controlled dimensions and diverse morphology. Gelurice® 48/16 (GLR) has been employed to stabilize the aqueous dispersion of Celecoxib (CXB) for enhancing its solubility and oral bioavailability. Our formula is composed of CXB loaded in polyvinylpyllodine (PVP) stabilized with GLR to formulate microparticles (MPs) (CXB-GLR-PVP MPs). CXB-GLR-PVP MPs display excellent in vitro properties regarding particle size (548 ± 10.23 nm), zeta potential (-20.21 ± 2.45 mV), and drug loading (DL, 1.98 ± 0.059 mg per 10 mg MPs). CXB-GLR-PVP MPs showed a significant (p < 0.05) higher % cumulative release after ten minutes (50.31 ± 4.36) compared to free CXB (10.63 ± 2.89). CXB exhibited good dispersibility, proved by X-ray diffractometry (XRD), adequate compatibility of all components, confirmed by Fourier-Transform Infrared Spectroscopy (FTIR), and spherical geometry as revealed in scanning electron microscopy (SEM). Concerning our anti-inflammatory study, there was a significant decrease in the scores of the inflammatory markers' immunostaining in the CXB-GLR-PVP MPs treated group. Also, the amounts of the oxidative stress biomarkers, as well as mRNA expression of interleukins (IL-1β and IL-6), considerably declined (p < 0.05) in CXB-GLR-PVP MPs treated group alongside an enhancement in the histological features was revealed. CXB-GLR-PVP MPs is an up-and-coming delivery system that could be elucidated in future clinical investigations.

Perspective insights into hydrogels and nanomaterials for ischemic stroke

Ischemic stroke (IS) is a neurological disorder prevalent worldwide with a high disability and mortality rate. In the clinic setting, tissue plasminogen activator (tPA) and thrombectomy could restore blood flow of the occlusion region and improve the outcomes of IS patients; however, these therapies are restricted by a narrow time window. Although several preclinical trials have revealed the molecular and cellular mechanisms underlying infarct lesions, the translatability of most findings is unsatisfactory, which contributes to the emergence of new biomaterials, such as hydrogels and nanomaterials, for the treatment of IS. Biomaterials function as structural scaffolds or are combined with other compounds to release therapeutic drugs. Biomaterial-mediated drug delivery approaches could optimize the therapeutic effects based on their brain-targeting property, biocompatibility, and functionality. This review summarizes the advances in biomaterials in the last several years, aiming to discuss the therapeutic potential of new biomaterials from the bench to bedside. The promising prospects of new biomaterials indicate the possibility of an organic combination between materialogy and medicine, which is a novel field under exploration.

Insight into Fucoidan-Based PEGylated PLGA Nanoparticles Encapsulating Methyl Anthranilic Acid: In Vitro Evaluation and In Vivo Anti-Inflammatory Study

A potential fucoidan-based PEGylated PLGA nanoparticles (NPs) offering a proper delivery of N-methyl anthranilic acid (MA, a model of hydrophobic anti-inflammatory drug) have been developed via the formation of fucoidan aqueous coating surrounding PEGylated PLGA NPs. The optimum formulation (FuP2) composed of fucoidan:m-PEG-PLGA (1:0.5 w/w) with particle size (365 ± 20.76 nm), zeta potential (-22.30 ± 2.56 mV), % entrapment efficiency (85.45 ± 7.41), drug loading (51.36 ± 4.75 µg/mg of NPs), % initial burst (47.91 ± 5.89), and % cumulative release (102.79 ± 6.89) has been further investigated for the anti-inflammatory in vivo study. This effect of FuP2 was assessed in rats' carrageenan-induced acute inflammation model. The average weight of the paw edema was significantly lowered (p ≤ 0.05) by treatment with FuP2. Moreover, cyclooxygenase-2 and tumor necrosis factor-alpha immunostaining were decreased in FuP2 treated group compared to the other groups. The levels of prostaglandin E2, nitric oxide, and malondialdehyde were significantly reduced (p ≤ 0.05) in the FuP2-treated group. A significant reduction (p ≤ 0.05) in the expression of interleukins (IL-1β and IL-6) with an improvement of the histological findings of the paw tissues was observed in the FuP2-treated group. Thus, fucoidan-based PEGylated PLGA-MA NPs are a promising anti-inflammatory delivery system that can be applied for other similar drugs potentiating their pharmacological and pharmacokinetic properties.

New insights into ischemia-reperfusion injury signaling pathways in organ transplantation

PURPOSE OF REVIEW

Ischemia-reperfusion injury (IRI) leading to allograft rejection in solid organ transplant recipients is a devastating event that compromises graft and patient survival. As our clinical knowledge regarding its definition and presentation has significantly improved over the last years, adequate biomarkers translating to important therapeutic intervention remains a challenge. This review will summarize recent findings in this area.

RECENT FINDINGS

In the past 18 months, our understanding of organ transplantation IRI has improved. IRI involves a positive amplification feedback loop encompassing damaged cells at the graft site, the activity of redox-sensitive damage-associated molecular patterns, and local sequestration of recipient-derived monocytes, lymphocytes and polymorphonuclear leukocytes, like neutrophils, to sustain the immunological cascade and to enhance the destruction of the foreign tissue. Recent studies have identified critical components leading to IRI, including the oxidation state of high mobility group box 1, a classic danger signal, its role in the Toll-like receptor 4-interleukin (IL)-23-IL-17A signaling axis, and the role of neutrophils and CD321, a marker for transmigration of circulating leukocytes into the inflamed tissue. In addition, recent findings imply that the protective functions mediated by autophagy activation counterbalance the detrimental nucleotide-binding domain-like receptor family, pyrin domain containing 3 inflammasome pathway. Finally, clinical studies reveal the posttransplant variables associated with early allograft dysfunction and IRI.

SUMMARY

The future challenge will be understanding how crosstalk at the molecular and cellular levels integrate prospectively to predict which peri-transplant signals are essential for long-term clinical outcomes.

Microfluidic Model to Evaluate Astrocyte Activation in Penumbral Region following Ischemic Stroke

Stroke is one of the main causes of death in the US and post-stroke treatment options remain limited. Ischemic stroke is caused by a blood clot that compromises blood supply to the brain, rapidly leading to tissue death at the core of the infarcted area surrounded by a hypoxic and nutrient-starved region known as the penumbra. Recent evidence suggests that astrocytes in the penumbral region play a dual role in stroke response, promoting further neural and tissue damage or improving tissue repair depending on the microenvironment. Thus, astrocyte response in the hypoxic penumbra could promote tissue repair after stroke, salvaging neurons in the affected area and contributing to cognitive recovery. However, the complex microenvironment of ischemic stroke, characterized by gradients of hypoxia and nutrients, poses a unique challenge for traditional in vitro models, which in turn hinders the development of novel therapies. To address this challenge, we have developed a novel, polystyrene-based microfluidic device to model the necrotic and penumbral region induced by an ischemic stroke. We demonstrated that when subjected to hypoxia, and nutrient starvation, astrocytes within the penumbral region generated in the microdevice exhibited long-lasting, significantly altered signaling capacity including calcium signaling impairment.