Therapeutic Potential of Mesenchymal Stromal Cell-Derived Extracellular Vesicles in the Prevention of Organ Injuries Induced by Traumatic Hemorrhagic Shock

PRG4 mitigates hemorrhagic shock-induced cardiac injury by inhibiting mitochondrial dysregulation, oxidative stress and NLRP3-mediated pyroptosis

Hemorrhagic shock (HS) is one of the main causes of morbidity and death in patients with trauma or major surgery. Cardiac dysfunction is a well-known complication of HS. PRG4, also known as lubricin, is a mucin-like glycoprotein that plays anti-inflammatory and anti-apoptotic roles in a variety of diseases. In this study, we aimed to explore the cardioprotective efficacy of PRG4 in HS-induced cardiac injury. Employing the HS model and RNA-seq, we found that PRG4 was increased in the myocardial tissue of rats after HS. In vivo studies suggested that HS led to abnormal hemodynamic parameters and increased cTnI levels, and PRG4 overexpression effectively reversed these changes. PRG4 also suppressed HS-induced mitochondrial disorders, as reflected by increased mitochondrial membrane potential (MMP), ATP and mitochondria cytochrome c, COXIV and TOM20, as well as decreased BNIP3L and cytoplasmic cytochrome c. Furthermore, HS led to enhanced oxidative stress, as evidenced by upregulated ROS and MDA contents, and downregulated SOD and CAT activities, and these alterations were negated by PRG4 overexpression. Notably, PRG4 repressed the NLRP3-mediated pyroptosis pathway, as illustrated by decreased NLRP3 levels, caspase-1 activity and GSDMD-NT levels. In summary, these observations indicate that PRG4 overexpression protects against HS-induced cardiac dysfunction by inhibiting mitochondrial dysregulation, oxidative stress and NLRP3-mediated pyroptosis.

MKK3 depletion attenuates intestinal injury after traumatic hemorrhagic shock by restoring mitochondrial function

BACKGROUND

Traumatic hemorrhagic shock (THS) is a complex pathophysiological process resulting in multiple organ failure. Intestinal barrier dysfunction is one of the mechanisms implicated in multiple organ failure. The present study aimed to explore the regulatory role of mitogen-activated protein kinase kinase 3 (MKK3) in THS-induced intestinal injury and to elucidate its potential mechanism.

METHODS

Rats were subjected to trauma and hemorrhage to establish a THS animal model. MKK3-targeted lentiviral vectors were injected via the tail vein 72 h before modeling. Twelve hours post-modeling, the mean arterial pressure (MAP) and heart rate (HR) were monitored, and histological injury to the intestine was assessed via H&E staining and transmission electron microscopy. Mitochondrial function and mitochondrial reactive oxygen species (ROS) were evaluated. IEC-6 cells were exposed to hypoxia to mimic intestinal injury following THS in vitro.

RESULTS

MKK3 deficiency alleviated intestinal injury and restored mitochondrial function in intestinal tissues from THS-induced rats and hypoxia-treated IEC-6 cells. In addition, MKK3 deficiency promoted Sirt1/PGC-1α-mediated mitochondrial biogenesis and restricted Pink1/Parkin-mediated mitophagy in the injured intestine and IEC-6 cells. Furthermore, the protective effect of MKK3 knockdown against hypoxia-induced mitochondrial damage was strengthened upon simultaneous LC3B/Pink1/Parkin knockdown or weakened upon simultaneous Sirt1 knockdown.

CONCLUSION

MKK3 deficiency protected against intestinal injury induced by THS by promoting mitochondrial biogenesis and restricting excessive mitophagy.

Transforming research to improve therapies for trauma in the twenty-first century

Improvements have been made in optimizing initial care of trauma patients, both in prehospital systems as well as in the emergency department, and these have also favorably affected longer term outcomes. However, as specific treatments for bleeding are largely lacking, many patients continue to die from hemorrhage. Also, major knowledge gaps remain on the impact of tissue injury on the host immune and coagulation response, which hampers the development of interventions to treat or prevent organ failure, thrombosis, infections or other complications of trauma. Thereby, trauma remains a challenge for intensivists. This review describes the most pressing research questions in trauma, as well as new approaches to trauma research, with the aim to bring improved therapies to the bedside within the twenty-first century.

Mesenchymal stem cells overexpressing PBX1 alleviates haemorrhagic shock-induced kidney damage by inhibiting NF-κB activation

Mesenchymal stem cells (MSCs) have favourable outcomes in the treatment of kidney diseases. Pre-B-cell leukaemia transcription factor 1 (PBX1) has been reported to be a regulator of self-renewal of stem cells. Whether PBX1 is beneficial to MSCs in the treatment of haemorrhagic shock (HS)-induced kidney damage is unknown. We overexpressed PBX1 in rat bone marrow-derived mesenchymal stem cells (rBMSCs) and human bone marrow-derived mesenchymal stem cells (hBMSCs) to treat rats with HS and hypoxia-treated human proximal tubule epithelial cells (HK-2), respectively. The results indicated that PBX1 enhanced the homing capacity of rBMSCs to kidney tissues and that treatment with rBMSCs overexpressing PBX1 improved the indicators of kidney function, alleviated structural damage to kidney tissues. Furthermore, administration with rBMSCs overexpressing PBX1 inhibited HS-induced NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation and the release of proinflammatory cytokines, and further attenuated apoptosis. We then determined whether NF-κB, an important factor in NLRP3 activation and the regulation of inflammation, participates in HS-induced kidney damage, and we found that rBMSCs overexpressing PBX1 inhibited NF-κB activation by decreasing the p-IκBα/IκBα and p-p65/p65 ratios and inhibiting the nuclear translocation and decreasing the DNA-binding capacity of NF-κB. hBMSCs overexpressing PBX1 also exhibited protective effects on HK-2 cells exposed to hypoxia, as shown by the increase in cell viability, the mitigation of apoptosis, the decrease in inflammation, and the inhibition of NF-κB and NLRP3 inflammasome activation. Our study demonstrates that MSCs overexpressing PBX1 ameliorates HS-induced kidney damage by inhibiting NF-κB pathway-mediated NLRP3 inflammasome activation and the inflammatory response.

CD44+ and CD31+ extracellular vesicles (EVs) are significantly reduced in polytraumatized patients with hemorrhagic shock - evaluation of their diagnostic and prognostic potential

Background

Hemorrhagic shock (HS) is responsible for approximately 2 million deaths per year worldwide and is caused in 80% by polytrauma. These patients need a precise and quick diagnostic, which should be based on a combination of laboratory markers and radiological data. Extracellular vesicles (EVs) were described as potential new markers and mediators in trauma. The aim of the present study was to analyze, whether the surface epitopes of plasma-EVs reflect HS in polytraumatized patients and whether cell-specific EV subpopulations are useful diagnostic tools.

Material and methods

Plasma samples from polytraumatized patients (ISS ≥16) with HS (n=10) and without (n=15), were collected at emergency room (ER) and 24h after trauma. Plasma-EVs were isolated via size exclusion chromatography and EV-concentrations were detected by Coomassie Plus (Bradford) Assay. The EVs subpopulations were investigated by a bead-based multiplex flow cytometry measurement of surface epitopes and were compared with healthy controls (n=10). To investigate the diagnostic and prognostic potential of EVs subpopulations, results were correlated with clinical outcome parameters documented in the electronical patients' record.

Results

We observed a significant reduction of the total amount of plasma EVs in polytrauma patients with HS, as compared to polytrauma patients without HS and healthy controls. We found significant reduction of CD42a+ and CD41b+ (platelet-derived) EVs in all polytrauma patients, as well as a reduction of CD29+ EVs compared to healthy volunteers (*p<0.05). CD44+ and CD31+ EVs were specifically altered in patients with HS (*p<0.05). Both EV populations showed a moderate correlation (r² = 0.42) with the transfusion of erythrocyte concentrate, were associated with non-survival and the need for catecholamines (*p<0.05).

Conclusion

Our data reveal that polytrauma patients with a hemorrhagic shock are characterized by a reduction of CD44+ and CD31+ plasma-EVs. Both EV populations showed a moderate correlation with the need of erythrocyte transfusion, were associated with non-survival and the need for catecholamines.

Adenosine metabolized from extracellular ATP ameliorates organ injury by triggering A2BR signaling

BACKGROUND

Trauma and a subsequent hemorrhagic shock (T/HS) result in insufficient oxygen delivery to tissues and multiple organ failure. Extracellular adenosine, which is a product of the extracellular degradation of adenosine 5' triphosphate (ATP) by the membrane-embedded enzymes CD39 and CD73, is organ protective, as it participates in signaling pathways, which promote cell survival and suppress inflammation through adenosine receptors including the A2BR. The aim of this study was to evaluate the role of CD39 and CD73 delivering adenosine to A2BRs in regulating the host's response to T/HS.

METHODS

T/HS shock was induced by blood withdrawal from the femoral artery in wild-type, global knockout (CD39, CD73, A2BR) and conditional knockout (intestinal epithelial cell-specific deficient VillinCre-A2BRfl/fl) mice. At 3 three hours after resuscitation, blood and tissue samples were collected to analyze organ injury.

RESULTS

T/HS upregulated the expression of CD39, CD73, and the A2BR in organs. ATP and adenosine levels increased after T/HS in bronchoalveolar lavage fluid. CD39, CD73, and A2BR mimics/agonists alleviated lung and liver injury. Antagonists or the CD39, CD73, and A2BR knockout (KO) exacerbated lung injury, inflammatory cytokines, and chemokines as well as macrophage and neutrophil infiltration and accumulation in the lung. Agonists reduced the levels of the liver enzymes aspartate transferase and alanine transaminase in the blood, whereas antagonist administration or CD39, CD73, and A2BR KO enhanced enzyme levels. In addition, intestinal epithelial cell-specific deficient VillinCre-A2BRfl/fl mice showed increased intestinal injury compared to their wild-type VillinCre controls.

CONCLUSION

In conclusion, the CD39-CD73-A2BR axis protects against T/HS-induced multiple organ failure.

A COMPARATIVE ANALYSIS TO DETERMINE THE OPTIMUM HISTONE DEACETYLASE INHIBITORS AND ADMINISTRATION ROUTE FOR IMPROVING SURVIVAL AND ORGAN INJURY IN RATS AFTER HEMORRHAGIC SHOCK

ABSTRACT

Objective: Histone deacetylase inhibitors (HDACIs) have been reported to improve survival in rats with hemorrhagic shock (HS). However, no consensus exists on the most effective HDACIs and their administration routes. We herein aimed to determine the optimal HDACIs and administration route in rats with HS. Methods: Survival analysis: In experiment I, male Sprague-Dawley rats were subjected to HS (mean arterial pressure [MAP] was maintained at 30-40 mm Hg for 20 min), and intravenously injected with the following agents (n = 8 per group): (1) no treatment, (2) vehicle (VEH), (3) entinostat (MS-275), (4) [ N -((6-(Hydroxyamino)-6-oxohexyl)oxy)-3,5-dimethylbenzamide] (LMK-235), (5) tubastatin A, (6) trichostatin A (TSA), and (7) sirtinol. In experiment II, rats were intraperitoneally injected with TSA. Mechanism research: In experiments I and II, rats were observed for 3 h, after which blood samples and liver, heart, and lung tissues were harvested. Results: In experiment I, 75% rats in the VEH group but only 25% rats in the LMK-235 and sirtinol groups died within ≤5 h of treatment, whereas the survival of rats in the MS-275, tubastatin A, and TSA groups was significantly prolonged. MS-275, LMK-235, tubastatin A, and TSA significantly reduced histopathological scores, apoptosis cell numbers, and inflammatory cytokine levels. In experiment II, the survival was longer after i.v. TSA treatment than after i.p. TSA treatment, and the IL-6 levels in the heart were significantly lower in rat who received i.p. TSA treatment than in those who received i.v. TSA treatment. Conclusions: The i.v. effect was superior to the i.p. effect, while nonselective and isoform-specific classes I and IIb HDACIs had similar effects.

Efficacy comparison of restrictive versus massive fluid resuscitation in patients with traumatic hemorrhagic shock

OBJECTIVE

To compare the therapeutic effect and safety of restrictive versus massive fluid resuscitation in patients with traumatic hemorrhagic shock (TSH).

METHODS

Ninety TSH patients treated in the ICU of the Second Affiliated Hospital of Zhejiang University School of Medicine from June 2020 to January 2021 were recruited for this retrospective study. Among them, 47 cases received restrictive fluid resuscitation (RFR) after admission who were considered as the observation group (OG), while the other 43 cases were given massive fluid resuscitation (MFR) who were treated as the control group (CG). The clinical indices, coagulation function, blood gas analysis, mortality within 72 h, duration of mechanical ventilation, and ICU stay were compared between the two groups, and the amount of resuscitation fluid given and complications that occurred during treatment were recorded. Multivariate logistic regression analysis was used to screen the independent risk factors for complications.

RESULTS

In comparison to the CG, the resuscitation time, infusion volume, and lactate level in the OG were lower after treatment, while the hemoglobin level and blood gas residual base value (BE) were higher. Besides, the activated partial thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT) levels and arterial blood carbon dioxide partial pressure (PaCO₂) in the OG were lower, while arterial blood oxygen partial pressure (PaO₂) and pH were higher. The duration of mechanical ventilation and ICU stay in the OG after treatment were lower, and there was no statistical difference in mortality and complication rates within 72 h. Lower mean arterial pressure (MAP), higher APACHE II (Acute Physiology and Chronic Health Evaluation II) and longer resuscitation time were independent risk factors for complications in patients with traumatic shock.

CONCLUSION

TSH treatment with RFR can effectively accelerate patients' resuscitation with less volume of infusion of resuscitation fluid, reduced time of mechanical ventilation and ICU hospitalization, and promote the recovery of coagulation function. It has good effects and is very suitable for clinical application.

Innate immunity and immunotherapy for hemorrhagic shock

Hemorrhagic shock (HS) is a shock result of hypovolemic injury, in which the innate immune response plays a central role in the pathophysiology ofthe severe complications and organ injury in surviving patients. During the development of HS, innate immunity acts as the first line of defense, mediating a rapid response to pathogens or danger signals through pattern recognition receptors. The early and exaggerated activation of innate immunity, which is widespread in patients with HS, results in systemic inflammation, cytokine storm, and excessive activation of complement factors and innate immune cells, comprised of type II innate lymphoid cells, CD4⁺ T cells, natural killer cells, eosinophils, basophils, macrophages, neutrophils, and dendritic cells. Recently, compelling evidence focusing on the innate immune regulation in preclinical and clinical studies promises new treatment avenues to reverse or minimize HS-induced tissue injury, organ dysfunction, and ultimately mortality. In this review, we first discuss the innate immune response involved in HS injury, and then systematically detail the cutting-edge therapeutic strategies in the past decade regarding the innate immune regulation in this field; these strategies include the use of mesenchymal stem cells, exosomes, genetic approaches, antibody therapy, small molecule inhibitors, natural medicine, mesenteric lymph drainage, vagus nerve stimulation, hormones, glycoproteins, and others. We also reviewed the available clinical studies on immune regulation for treating HS and assessed the potential of immune regulation concerning a translation from basic research to clinical practice. Combining therapeutic strategies with an improved understanding of how the innate immune system responds to HS could help to identify and develop targeted therapeutic modalities that mitigate severe organ dysfunction, improve patient outcomes, and reduce mortality due to HS injury.

MECHANISM OF MIR-25-3P CARRIED BY EXTRACELLULAR VESICLES DERIVED FROM PLATELET-RICH PLASMA IN IL-1β-INDUCED NUCLEUS PULPOSUS CELL DEGENERATION VIA THE SOX4/CXCR7 AXIS

ABSTRACT

Objectives: Nucleus pulposus (NP) cell degeneration promotes the progression of intervertebral disc (IVD) degeneration. MicroRNAs (miRs) are associated with IVD degeneration. This study expounded the mechanism of microRNA (miR)-25-3p carried by extracellular vesicles (EVs) derived from platelet-rich plasma (PRP) in interleukin (IL)-1β-induced NP cell degeneration. Methods: Platelet-rich plasma from mouse blood was obtained, and EVs were isolated from PRP (EVs derived from PRP [PRP-EVs]) and identified. Nucleus pulposus cells were isolated from the mouse lumbar IVD and treated with IL-1β to induce NP cell degeneration. Extracellular vesicles derived from PRP were added into NP cell culture medium. Afterward, intracellular miR-25-3p, sex determining region Y-related high-mobility-group box 4 (SOX4), and CXC chemokine receptor 7 (CXCR7) levels were examined. Nucleus pulposus cell viability, apoptosis, and inflammation were detected. Extracellular vesicles derived from PRP were labeled by PKH67 to obverse the uptake of EVs by NP cells. The binding relations between SOX4 and miR-25-3p and CXCR7 were predicted and examined. Functional rescue experiments were performed to investigate the roles of miR-25-3p, SOX4, and CXCR7 in NP cell degeneration. Results: miR-25-3p was downregulated, whereas SOX4 and CXCR7 were upregulated in IL-1β-induced NP cells. Extracellular vesicles derived from PRP increased the cell viability, and decreased apoptosis and inflammation. miR-25-3p carried by PRP-EVs into NP cells alleviated NP cell degeneration. miR-25-3p inhibited SOX4 expression and limited CXCR7 transcription. Silencing miR-25-3p or overexpressing SOX4 or CXCR7 reversed the alleviating role of PRP-EVs in NP cell degeneration. Conclusion: miR-25-3p carried by PRP-EVs into NP cells elevated intracellular miR-25-3p expression, which suppressed SOX4 expression and further limited CXCR7 transcription, thus alleviating IL-1β-induced NP cell degeneration. Extracellular vesicles derived from PRP containing miR-25-3p may be a new method for IVD treatment.

Mesenchymal Stromal Cells for Enhancing Hematopoietic Engraftment and Treatment of Graft-Versus-Host Disease, Hemorrhages and Acute Respiratory Distress Syndrome

Mesenchymal stromal cells (MSCs) possess profound immunomodulatory and regenerative properties that are of clinical use in numerous clinical indications with unmet medical need. Common sources of MSCs include among others, bone marrow (BM), fat, umbilical cord, and placenta-derived decidua stromal cells (DSCs). We here summarize our more than 20-years of scientific experience in the clinical use of MSCs and DSCs in different clinical settings. BM-MSCs were first explored to enhance the engraftment of autografts in hematopoietic cell transplantation (HCT) and osteogenesis imperfecta around 30 years ago. In 2004, our group reported the first anti-inflammatory use of BM-MSCs in a child with grade IV acute graft-versus-host disease (GvHD). Subsequent studies have shown that MSCs appear to be more effective in acute than chronic GvHD. Today BM-MSC-therapy is registered for acute GvHD in Japan and for GvHD in children in Canada and New Zeeland. MSCs first home to the lung following intravenous injection and exert strong local and systemic immunomodulatory effects on the host immune system. Thus, they were studied for ameliorating the cytokine storm in acute respiratory distress syndrome (ARDS). Both, MSCs and DSCs were used to treat SARS-CoV-2 coronavirus-induced disease 2019 (COVID-19)-induced ARDS. In addition, they were also used for other novel indications, such as pneumomediastinum, colon perforation, and radiculomyelopathy. MSC and DSCs trigger coagulation and were thus explored to stop hemorrhages. DSCs appear to be more effective for acute GvHD, ARDS, and hemorrhages, but randomized studies are needed to prove superiority. Stromal cell infusion is safe, well tolerated, and only gives rise to a slight fever in a limited number of patients, but no major side effects have been reported in multiple safety studies and metaanalysis. In this review we summarize current evidence from in vitro studies, animal models, and importantly our clinical experience, to support stromal cell therapy in multiple clinical indications. This encloses MSC’s effects on the immune system, coagulation, and their safety and efficacy, which are discussed in relation to prominent clinical trials within the field.