Proteomic Assessment of Hypoxia-Pre-Conditioned Human Bone Marrow Mesenchymal Stem Cell-Derived Extracellular Vesicles Demonstrates Promise in the Treatment of Cardiovascular Disease

Human bone marrow mesenchymal stem cell derived-extracellular vesicles (HBMSC-EV) are known for their regenerative and anti-inflammatory effects in animal models of myocardial ischemia. However, it is not known whether the efficacy of the EVs can be modulated by pre-conditioning of HBMSC by exposing them to either starvation or hypoxia prior to EV collection. HBMSC-EVs were isolated following normoxia starvation (NS), normoxia non-starvation (NNS), hypoxia starvation (HS), or hypoxia non-starvation (HNS) pre-conditioning. The HBMSC-EVs were characterized by nanoparticle tracking analysis, electron microscopy, Western blot, and proteomic analysis. Comparative proteomic profiling revealed that starvation pre-conditioning led to a smaller variety of proteins expressed, with the associated lesser effect of normoxia versus hypoxia pre-conditioning. In the absence of starvation, normoxia and hypoxia pre-conditioning led to disparate HBMSC-EV proteomic profiles. HNS HBMSC-EV was found to have the greatest variety of proteins overall, with 74 unique proteins, the greatest number of redox proteins, and pathway analysis suggestive of improved angiogenic properties. Future HBMSC-EV studies in the treatment of cardiovascular disease may achieve the most therapeutic benefits from hypoxia non-starved pre-conditioned HBMSC. This study was limited by the lack of functional and animal models of cardiovascular disease and transcriptomic studies.

Interferon-Gamma Primed Human Clonal Mesenchymal Stromal Cell Sheets Exhibit Enhanced Immunosuppressive Function

Mesenchymal stromal cells (MSCs) represent a promising treatment for immune-related diseases due to their diverse immunomodulatory paracrine functions. However, progress of culture-expanded MSCs is hindered by inconsistent cell function, poor localization, and insufficient retention when administered as suspended cell injections, thus placing spatiotemporal dosing constraints on therapeutic functions. To address these limitations, we introduce the combination of in vitro interferon-gamma (IFN-γ) priming, a key stimulator of MSC immunosuppressive potency, and thermoresponsive cultureware to harvest cultured MSCs as directly transplantable scaffold-free immunosuppressive cell sheets. Here, we demonstrate that MSC sheets produced with IFN-γ priming upregulate expression of immunosuppressive factors indoleamine 2,3-dioxygenase (IDO-1), interleukin-10 (IL-10), programmed death ligand-1 (PD-L1), and prostaglandin E2 (PGE2) in both dose- and duration-dependent manners. In addition, IFN-γ primed MSC sheets showed increased ability to inhibit T-cell proliferation via indirect and direct contact, specifically related to increased IDO-1 and PGE2 concentrations. Furthermore, this study's use of human clinical-grade single-cell-derived clonal bone marrow-derived MSCs, contributes to the future translatability and clinical relevancy of the produced sheets. Ultimately, these results present the combination of IFN-γ priming and MSC sheets as a new strategy to improve MSC-mediated treatment of localized inflammatory diseases.

Pre-Conditioning with IFN-γ and Hypoxia Enhances the Angiogenic Potential of iPSC-Derived MSC Secretome

Induced pluripotent stem cell (iPSC) derived mesenchymal stem cells (iMSCs) represent a promising source of progenitor cells for approaches in the field of bone regeneration. Bone formation is a multi-step process in which osteogenesis and angiogenesis are both involved. Many reports show that the secretome of mesenchymal stromal stem cells (MSCs) influences the microenvironment upon injury, promoting cytoprotection, angiogenesis, and tissue repair of the damaged area. However, the effects of iPSC-derived MSCs secretome on angiogenesis have seldom been investigated. In the present study, the angiogenic properties of IFN-γ pre-conditioned iMSC secretomes were analyzed. We detected a higher expression of the pro-angiogenic genes and proteins of iMSCs and their secretome under IFN-γ and hypoxic stimulation (IFN-H). Tube formation and wound healing assays revealed a higher angiogenic potential of HUVECs in the presence of IFN-γ conditioned iMSC secretome. Sprouting assays demonstrated that within Coll/HA scaffolds, HUVECs spheroids formed significantly more and longer sprouts in the presence of IFN-γ conditioned iMSC secretome. Through gene expression analyses, pro-angiogenic genes (FLT-1, KDR, MET, TIMP-1, HIF-1α, IL-8, and VCAM-1) in HUVECs showed a significant up-regulation and down-regulation of two anti-angiogenic genes (TIMP-4 and IGFBP-1) compared to the data obtained in the other groups. Our results demonstrate that the iMSC secretome, pre-conditioned under inflammatory and hypoxic conditions, induced the highest angiogenic properties of HUVECs. We conclude that pre-activated iMSCs enhance their efficacy and represent a suitable cell source for collagen/hydroxyapatite with angiogenic properties.

Heavy Metal Pre-Conditioning History Modulates Spartina patens Physiological Tolerance along a Salinity Gradient

Land salinization, resulting from the ongoing climate change phenomena, is having an increasing impact on coastal ecosystems like salt marshes. Although halophyte species can live and thrive in high salinities, they experience differences in their salt tolerance range, being this a determining factor in the plant distribution and frequency throughout marshes. Furthermore, intraspecific variation to NaCl response is observed in high-ranging halophyte species at a population level. The present study aims to determine if the environmental history, namely heavy metal pre-conditioning, can have a meaningful influence on salinity tolerance mechanisms of Spartina patens, a highly disperse grass invader in the Mediterranean marshes. For this purpose, individuals from pristine and heavy metal contaminated marsh populations were exposed to a high-ranging salinity gradient, and their intraspecific biophysical and biochemical feedbacks were analyzed. When comparing the tolerance mechanisms of both populations, S. patens from the contaminated marsh appeared to be more resilient and tolerant to salt stress, this was particularly present at the high salinities. Consequently, as the salinity increases in the environment, the heavy metal contaminated marsh may experience a more resilient and better adapted S. patens community. Therefore, the heavy metal pre-conditioning of salt mash populations appears to be able to create intraspecific physiological variations at the population level that can have a great influence on marsh plant distribution outcome.

Chromatin Dynamics and Gene Expression Response to Heat Exposure in Field-Conditioned versus Laboratory-Cultured Nematostella vectensis

Organisms’ survival is associated with the ability to respond to natural or anthropogenic environmental stressors. Frequently, these responses involve changes in gene regulation and expression, consequently altering physiology, development, or behavior. Here, we present modifications in response to heat exposure that mimics extreme summertime field conditions of lab-cultured and field-conditioned Nematostella vectensis. Using ATAC-seq and RNA-seq data, we found that field-conditioned animals had a more concentrated reaction to short-term thermal stress, expressed as enrichment of the DNA repair mechanism pathway. By contrast, lab animals had a more diffuse reaction that involved a larger number of differentially expressed genes and enriched pathways, including amino acid metabolism. Our results demonstrate that pre-conditioning affects the ability to respond efficiently to heat exposure in terms of both chromatin accessibility and gene expression and reinforces the importance of experimentally addressing ecological questions in the field.

Pre-conditioning modifies the TME to enhance solid tumor CAR T cell efficacy and endogenous protective immunity

Chimeric antigen receptor (CAR) T cell therapy has led to impressive clinical responses in patients with hematological malignancies; however, its effectiveness in patients with solid tumors has been limited. While CAR T cells for the treatment of advanced prostate and pancreas cancer, including those targeting prostate stem cell antigen (PSCA), are being clinically evaluated and are anticipated to show bioactivity, their safety and the impact of the immunosuppressive tumor microenvironment (TME) have not been faithfully explored preclinically. Using a novel human PSCA knockin (hPSCA-KI) immunocompetent mouse model, we evaluated the safety and therapeutic efficacy of PSCA-CAR T cells. We demonstrated that cyclophosphamide (Cy) pre-conditioning significantly modified the immunosuppressive TME and was required to uncover the efficacy of PSCA-CAR T cells in metastatic prostate and pancreas cancer models, with no observed toxicities in normal tissues with endogenous expression of PSCA. This combination dampened the immunosuppressive TME, generated pro-inflammatory myeloid and T cell signatures in tumors, and enhanced the recruitment of antigen-presenting cells, as well as endogenous and adoptively transferred T cells, resulting in long-term anti-tumor immunity.

Anaesthesia and ICU sedation with sevoflurane do not reduce myocardial injury in patients undergoing cardiac surgery: A randomized prospective study

BACKGROUND

To evaluate the effect of anaesthesia and ICU sedation with sevoflurane to protect the myocardium against ischemia-reperfusion injury associated to cardiac surgery assessed by troponin release.

METHODS

We performed a prospective, open-label, randomized study in cardiac surgery with cardiopulmonary bypass. Patients were randomized to an algorithm-based intervention group and a control group. The main outcome was the perioperative kinetic of cardiac troponin I (cTnI). The secondary outcomes included composite endpoint, GDF-15 (macrophage inhibitory cytokine-1) value, arterial lactate levels, and the length of stay (LOS) in the ICU.

RESULTS

Of 82 included patients, 81 were analyzed on an intention-to-treat basis (intervention group: n = 42; control group: n = 39). On inclusion, the intervention and control groups did not differ significantly in terms of demographic and surgical data. The postoperative kinetics of cTnI did not differ significantly between groups: the mean difference was 0.44 ± 1.09 μg/ml, P = .69. Incidence of composite endpoint and GDF-15 values were higher in the sevoflurane group than in propofol group. The intervention and control groups did not differ significantly in terms of ICU stay and hospital stay.

CONCLUSION

The use of an anaesthesia and ICU sedation with sevoflurane was not associated with a lower incidence of myocardial injury assessed by cTnI. Sevoflurane administration was associated with higher prevalence of acute renal failure and higher GDF-15 values.

Current Knowledge and Future Perspectives on Mesenchymal Stem Cell-Derived Exosomes as a New Therapeutic Agent. Int J Mol Sci. 2020;21:727. [PMID: 31979113 PMCID: PMC7036914 DOI: 10.3390/ijms21030727]

Mesenchymal stem cells (MSCs) are on the cusp of regenerative medicine due to their differentiation capacity, favorable culture conditions, ability to be manipulated in vitro, and strong immunomodulatory activity. Recent studies indicate that the pleiotropic effects of MSCs, especially their immunomodulatory potential, can be largely attributed to paracrine factors. Exosomes, vesicles that are 30-150 nanometers in diameter that function in cell-cell communication, are one of the key paracrine effectors. MSC-derived exosomes are enriched with therapeutic miRNAs, mRNAs, cytokines, lipids, and growth factors. Emerging evidences support the compelling possibility of using MSC-derived exosomes as a new form of therapy for treating several different kinds of disease such as heart, kidney, immune diseases, neural injuries, and neurodegenerative disease. This review provides a summary of current knowledge and discusses engineering of MSC-derived exosomes for their use in translational medicine.

Static Metabolic Bubbles as Precursors of Vascular Gas Emboli During Divers' Decompression: A Hypothesis Explaining Bubbling Variability

Introduction

The risk for decompression sickness (DCS) after hyperbaric exposures (such as SCUBA diving) has been linked to the presence and quantity of vascular gas emboli (VGE) after surfacing from the dive. These VGE can be semi-quantified by ultrasound Doppler and quantified via precordial echocardiography. However, for an identical dive, VGE monitoring of divers shows variations related to individual susceptibility, and, for a same diver, dive-to-dive variations which may be influenced by pre-dive pre-conditioning. These variations are not explained by currently used algorithms. In this paper, we present a new hypothesis: individual metabolic processes, through the oxygen window (OW) or Inherent Unsaturation of tissues, modulate the presence and volume of static metabolic bubbles (SMB) that in turn act as precursors of circulating VGE after a dive.

Methods

We derive a coherent system of assumptions to describe static gas bubbles, located on the vessel endothelium at hydrophobic sites, that would be activated during decompression and become the source of VGE. We first refer to the OW and show that it creates a local tissue unsaturation that can generate and stabilize static gas phases in the diver at the surface. We then use Non-extensive thermodynamics to derive an equilibrium equation that avoids any geometrical description. The final equation links the SMB volume directly to the metabolism.

Results and Discussion

Our model introduces a stable population of small gas pockets of an intermediate size between the nanobubbles nucleating on the active sites and the VGE detected in the venous blood. The resulting equation, when checked against our own previously published data and the relevant scientific literature, supports both individual variation and the induced differences observed in pre-conditioning experiments. It also explains the variability in VGE counts based on age, fitness, type and frequency of physical activities. Finally, it fits into the general scheme of the arterial bubble assumption for the description of the DCS risk.

Conclusion

Metabolism characterization of the pre-dive SMB population opens new possibilities for decompression algorithms by considering the diver's individual susceptibility and recent history (life style, exercise) to predict the level of VGE during and after decompression.

Blood-Flow Restricted Warm-Up Alters Muscle Hemodynamics and Oxygenation during Repeated Sprints in American Football Players

Team-sport athletes and coaches use varied strategies to enhance repeated-sprint ability (RSA). Aside from physical training, a well-conducted warm-up enhances RSA via increased oxidative metabolism. Strategies that impede blood flow could potentiate the effects of a warm-up due to their effects on the endothelial and metabolic functions. This study investigated whether performing a warm-up combined with blood-flow restriction (WFR) induces ergogenic changes in blood volume, muscle oxygenation, and RSA. In a pair-matched, single-blind, pre-post parallel group design, 15 American football players completed an RSA test (12 × 20 m, 20 s rest), preceded by WFR or a regular warm-up (SHAM). Pressure was applied on the athletes’ upper thighs for ≈15 min using elastic bands. Both legs were wrapped at a perceived pressure of 7 and 3 out of 10 in WFR and SHAM, respectively. Changes in gastrocnemius muscle oxygen saturation (S_mO₂) and total hemoglobin concentration ([THb]) were monitored with near-infrared spectroscopy. Cohen’s effect sizes (ES) were used to estimate the impact of WFR. WFR did not clearly alter best sprint time (ES −0.25), average speed (ES 0.25), total time (ES −0.12), and percent decrement score (ES 0.39). While WFR did not meaningfully alter average S_mO₂ and [THb], the intervention clearly increased the maximum [THb] and the minimum and maximum S_mO₂ during some of the 12 sprint/recovery periods (ES 0.34–1.43). Results indicate that WFR positively alters skeletal muscle hemodynamics during an RSA test. These physiological changes did not improve short-term RSA, but could be beneficial to players during longer activities such as games.

Parallel comparison of pre-conditioning and post-conditioning effects in human cancers and keratinocytes upon acute gamma irradiation

PURPOSE

To determine and compare the effects of pre-conditioning and post-conditioning towards gamma radiation responses in human cancer cells and keratinocytes.

MATERIAL AND METHODS

The clonogenic survival of glioblastoma cells (T98G), keratinocytes (HaCaT), and colorectal carcinoma cells (HCT116 p53^+/+ and p53^-/-) was assessed following gamma ray exposure from a Cs-137 source. The priming dose preceded the challenge dose in pre-conditioning whereas the priming dose followed the challenge dose in post-conditioning. The priming dose was either 5 mGy or 0.1 Gy. The challenge dose was 0.5-5 Gy.

RESULTS

In both pre- and post-conditioning where the priming dose was 0.1 Gy and the challenge dose was 4 Gy, RAR developed in T98G but not in HaCaT cells. In HCT116 p53^+/+, pre-conditioning had either no effect or a radiosensitizing effect and whereas post-conditioning induced either radiosensitizing or radioadaptive effect. The different observed outcomes were dependent on dose, the time interval between the priming and challenge dose, and the time before the first irradiation. Post-conditioning effects could occur with a priming dose as low as 5 mGy in HCT116 p53^+/+ cells. When HCT116 cells had no p53 protein expression, the radiosensitizing or radioadaptive response by the conditioning effect was abolished.

CONCLUSIONS

The results suggest that radiation conditioning responses are complex and depend on at least the following factors: the magnitude of priming/challenge dose, the time interval between priming and challenge dose, p53 status, cell seeding time prior to the first radiation treatment. This work is the first parallel comparison demonstrating the potential outcomes of pre- and post-conditioning in different human cell types using environmentally and medically relevant radiation doses.

Mesenchymal Stromal Cell Secretome: Influencing Therapeutic Potential by Cellular Pre-conditioning

Mesenchymal stromal cells (MSCs) are self-renewing, culture-expandable adult stem cells that have been isolated from a variety of tissues, and possess multipotent differentiation capacity, immunomodulatory properties, and are relatively non-immunogenic. Due to this unique set of characteristics, these cells have attracted great interest in the field of regenerative medicine and have been shown to possess pronounced therapeutic potential in many different pathologies. MSCs' mode of action involves a strong paracrine component resulting from the high levels of bioactive molecules they secrete in response to the local microenvironment. For this reason, MSCs' secretome is currently being explored in several clinical contexts, either using MSC-conditioned media (CM) or purified MSC-derived extracellular vesicles (EVs) to modulate tissue response to a wide array of injuries. Rather than being a constant mixture of molecular factors, MSCs' secretome is known to be dependent on the diverse stimuli present in the microenvironment that MSCs encounter. As such, the composition of the MSCs' secretome can be modulated by preconditioning the MSCs during in vitro culture. This manuscript reviews the existent literature on how preconditioning of MSCs affects the therapeutic potential of their secretome, focusing on MSCs' immunomodulatory and regenerative features, thereby providing new insights for the therapeutic use of MSCs' secretome.

Acoustic Methods for Increasing the Cavitation Initiation Pressure Threshold

Histotripsy is a tissue ablation method that utilizes focused, high-amplitude ultrasound to generate a cavitation bubble cloud that mechanically fractionates tissue. Effective histotripsy depends on the initiation, control, and maintenance of cavitation bubble clouds in the targeted area. In this study, we hypothesized that a low-pressure acoustic pulse sequence applied before and/or during histotripsy therapy would increase the cavitation initiation pressure threshold and the growth of cavitation bubble clouds. This technique could shrink or "sharpen" the focal zone during histotripsy to produce more precise and well-defined lesions with minimal collateral damage. It may also be a way to actively protect the soft tissue from cavitation damage during lithotripsy by increasing the pressure threshold for bubble cloud initiation. We applied these low-amplitude acoustic pulse sequences before and during histotripsy treatments with the pulse repetition frequency of 1 and 100 Hz, in three different mediums: water, tissue phantom agarose gel, and bovine liver in vitro. Acoustic backscatter signals and optical imaging were used to detect and monitor the initiation, maintenance, and growth of the resulting cavitation bubble cloud. The results demonstrated that the use of low-amplitude acoustic pulse sequences could increase the cavitation pressure amplitude threshold by 20% in the targeted area.

Hormesis: Path and Progression to Significance

This paper tells the story of how hormesis became recognized as a fundamental concept in biology, affecting toxicology, microbiology, medicine, public health, agriculture, and all areas related to enhancing biological performance. This paper assesses how hormesis enhances resilience to normal aging and protects against a broad spectrum of neurodegenerative, cardiovascular, and other diseases, as well as trauma and other threats to health and well-being. This paper also explains the application of hormesis to several neurodegenerative diseases such as Parkinson’s and Huntington’s disease, macrophage polarization and its systematic adaptive protections, and the role of hormesis in enhancing stem cell functioning and medical applications.

Comparison of propofol-based versus volatile-based anaesthesia and postoperative sedation in cardiac surgical patients: a prospective, randomized, study

BACKGROUND

Clinical trials have shown conflicting results regarding the use of volatile anaesthesia before or after an ischaemic insult in cardiac surgical patients and its effect on myocardial injury. This may be attributable to the failure of continuing volatile agents into the early postoperative period. We hypothesised that combined volatilebased anaesthesia and postoperative sedation would decrease the extent of myocardial injury after coronary artery bypass grafting (CABG) when compared with an intravenous, propofol-based approach. This study aimed to assess the feasibility of the perioperative protocol and investigate whether volatile anaesthesia provides cardioprotection in patients undergoing CABG.

METHODS

Randomized, controlled trial enrolling 157 patients with preserved left ventricular function scheduled for elective or urgent on-pump CABG. Patients received either volatile- or propofol-based anaesthesia and postoperative sedation. Volatile sedation in the ICU was provided with the use of the AnaConDa® device (Sedana Medical, Uppsala, Sweden). The primary outcome was myocardial injury measured by serial troponin measurement at the beginning of surgery, 2, 4 and 12-16 h after ICU admission. The secondary outcome was cardiac performance expressed as cardiac index (CI) and the need for inotropic and vasopressor drug support. The peak postoperative troponin level was defined as the highest level at any time in the first 16 h after surgery.

RESULTS

127 patients completed the study protocol, 60 patients in the volatile group and 67 patients in the propofol group. Troponin levels were similar between groups at all of the measured time points. There were no differences in cardiac index or vasoactive drug support except for the immediate post- cardiopulmonary bypass (CPB) period when patients in the volatile group had low systemic vascular resistance, high CI and required more vasopressors. There was no difference in postoperative kidney function, intensive care unit discharge or hospital discharge time.

CONCLUSIONS

The use of volatile-based anaesthesia and postoperative sedation did not confer any cardioprotection compared with propofol-based anaesthesia and sedation in patients who had good left ventricular function and were undergoing CABG.

Metabolomics in Plant Priming Research: The Way Forward?

A new era of plant biochemistry at the systems level is emerging, providing detailed descriptions of biochemical phenomena at the cellular and organismal level. This new era is marked by the advent of metabolomics—the qualitative and quantitative investigation of the entire metabolome (in a dynamic equilibrium) of a biological system. This field has developed as an indispensable methodological approach to study cellular biochemistry at a global level. For protection and survival in a constantly-changing environment, plants rely on a complex and multi-layered innate immune system. This involves surveillance of ‘self’ and ‘non-self,’ molecule-based systemic signalling and metabolic adaptations involving primary and secondary metabolites as well as epigenetic modulation mechanisms. Establishment of a pre-conditioned or primed state can sensitise or enhance aspects of innate immunity for faster and stronger responses. Comprehensive elucidation of the molecular and biochemical processes associated with the phenotypic defence state is vital for a better understanding of the molecular mechanisms that define the metabolism of plant–pathogen interactions. Such insights are essential for translational research and applications. Thus, this review highlights the prospects of metabolomics and addresses current challenges that hinder the realisation of the full potential of the field. Such limitations include partial coverage of the metabolome and maximising the value of metabolomics data (extraction of information and interpretation). Furthermore, the review points out key features that characterise both the plant innate immune system and enhancement of the latter, thus underlining insights from metabolomic studies in plant priming. Future perspectives in this inspiring area are included, with the aim of stimulating further studies leading to a better understanding of plant immunity at the metabolome level.

Connexins and Nitric Oxide Inside and Outside Mitochondria: Significance for Cardiac Protection and Adaptation

Irreversible myocardial damage happens in the presence of prolonged and severe ischemia. Several phenomena protect the heart against myocardial infarction and other adverse outcomes of ischemia and reperfusion (IR), namely: hibernation related to stunned myocardium, ischemic preconditioning (IPC), ischemic post-conditioning, and their pharmacological surrogates. Ischemic preconditioning consists in the induction of a brief IR to reduce damage of the tissue caused by prolonged and severe ischemia. Nitric oxide (NO) signaling plays an essential role in IPC. Nitric oxide-sensitive guanylate cyclase/cyclic guanosine-3′,5′-monophosphate (cGMP)-dependent protein kinase type I-signaling pathway protects against the IR injury during myocardial infarction. Mitochondrial ATP-sensitive and Ca²⁺-activated K⁺ channels are involved in NO-mediated signaling in IPC. Independently of the cGMP-mediated induction of NO production, S-nitrosation represents a regulatory molecular mechanism similar to phosphorylation and is essential for IPC. Unlike conditioning phenomena, the mechanistic basis of myocardial stunning and hibernation remains poorly understood. In this review article, we hypothesize that the disruption of electrical syncytium of the myocardium may underly myocardial stunning and hibernation. Considering that the connexins are the building blocks of gap junctions which represent primary structural basis of electrical syncytium, we discuss data on the involvement of connexins into myocardial conditioning, stunning, and hibernation. We also show how NO-mediated signaling is involved in myocardial stunning and hibernation. Connexins represent an essential element of adaptation phenomena of the heart at the level of both the cardio- myocytes and the mitochondria. Nitric oxide targets mitochondrial connexins which may affect electrical syncytium continuum in the heart. Mitochondrial connexins may play an essential role in NO-dependent mechanisms of myocardial adaptation to ischemia.

Synthetic CpG oligonucleotides induce a genetic profile ameliorating murine myocardial I/R injury

We previously demonstrated that pre‐conditioning with CpG oligonucleotide (ODN) 1668 induces quick up‐regulation of gene expression 3 hours post‐murine myocardial ischaemia/reperfusion (I/R) injury, terminating inflammatory processes that sustain I/R injury. Now, performing comprehensive microarray and biocomputational analyses, we sought to further enlighten the “black box” beyond these first 3 hours. C57BL/6 mice were pretreated with either CpG 1668 or with control ODN 1612, respectively. Sixteen hours later, myocardial ischaemia was induced for 1 hour in a closed‐chest model, followed by reperfusion for 24 hours. RNA was extracted from hearts, and labelled cDNA was hybridized to gene microarrays. Data analysis was performed with BRB ArrayTools and Ingenuity Pathway Analysis. Functional groups mediating restoration of cellular integrity were among the top up‐regulated categories. Genes known to influence cardiomyocyte survival were strongly induced 24 hours post‐I/R. In contrast, proinflammatory pathways were down‐regulated. Interleukin‐10, an upstream regulator, suppressed specifically selected proinflammatory target genes at 24 hours compared to 3 hours post‐I/R. The IL1 complex is supposed to be one regulator of a network increasing cardiovascular angiogenesis. The up‐regulation of numerous protective pathways and the suppression of proinflammatory activity are supposed to be the genetic correlate of the cardioprotective effects of CpG 1668 pre‐conditioning.

CD19 CAR T Cells Expressing IL-12 Eradicate Lymphoma in Fully Lymphoreplete Mice through Induction of Host Immunity

Chimeric antigen receptor (CAR) T cell therapy represents a significant advancement in cancer therapy. Larger studies have shown ∼90% complete remission rates against chemoresistant and/or refractory CD19⁺ leukemia or lymphoma. Effective CAR T cell therapy is highly dependent on lymphodepleting preconditioning, which is achieved through chemotherapy or radiotherapy that carries with it significant toxicities. These can exclude patients of low performance status. In order to overcome the need for preconditioning, we constructed fully mouse first and second generation anti-murine CD19 CARs with or without interleukin-12 (IL-12) secretion. To test these CARs, we established a mouse model to reflect the human situation without preconditioning. Murine second generation CAR T cells expressing IL-12 were capable of eradicating established B cell lymphoma with a long-term survival rate of ∼25%. We believe this to be the first study in a truly lymphoreplete model. We provide evidence that IL-12-expressing CAR T cells not only directly kill target CD19⁺ cells, but also recruit host immune cells to an anti-cancer immune response. This finding is critical because lymphodepletion regimens required for the success of current CAR T cell technology eliminate host immune cells whose anti-cancer activity could otherwise be harnessed by strategies such as IL-12-secreting CAR T cells.

Advances in molecular mechanism of cardioprotection induced by helium

Helium has been classified as a kind of inert gas that is not effortless to spark chemical reactions with other substances in the past decades. Nevertheless, the cognition of scientists has gradually changed accompanied with a variety of studies revealing the potential molecular mechanism underlying organ-protection induced by helium. Especially, as a non-anesthetic gas which is deficient of relevant cardiopulmonary side effects, helium conditioning is recognized as an emerging and promising approach to exert favorable effects by mimicking the cardioprotection of anesthetic gases or xenon. In this review we will summarize advances in the underlying biological mechanisms and clinical applicability with regards to the cardioprotective effects of helium.

Mode of perfusion influences infarct size, coronary flow and stress kinases in the isolated mouse heart

AIM

The isolated, retrogradely perfused heart (modified Langendorff model) is a widely used method in experimental heart research. The presence of an intraventricular balloon is necessary to get functional measurements. We have previously shown that the balloon induces phosphorylation of some suggested cardioprotective mitogen-activated protein kinases (MAPK): P38-MAPK, ERK 1/2 and JNK. We hypothesized that the balloon could influence cardioprotection, protect against ischaemia reperfusion injury and interfere with coronary flow.

METHODS AND RESULTS

Isolated mouse hearts were perfused for 5, 10, 20, 40 and 60 min with a balloon in the left ventricle. We found a wavelike phosphorylation of all MAPK while AKT displayed a gradual dephosphorylation when compared to non-perfused hearts. Hearts were subjected to 20 min of stabilization with or without the balloon, followed by 35 min of ischaemia and 120 min of reperfusion. Although the MAPK were phosphorylated, the infarcts were larger in the balloon group. When the balloon was present during the entire protocol, compared to removal at the end of ischaemia, the infarct size was also larger, especially in the endocardial layer. The balloon reduced post-ischaemic endocardial coronary flow, despite a higher average flow, indicating a hyperperfused epicard. Blocking the balloon-induced ERK 1/2 phosphorylation during stabilization did not affect infarct size. The effect of post-conditioning was influenced by the balloon, showing reduced infarct size when the balloon was present.

CONCLUSION

The balloon used for pressure measurements may contributes to cell death possibly by reducing endocardial coronary flow.

Neuroprotection provided by isoflurane pre-conditioning and post-conditioning

Isoflurane, a volatile and inhalational anesthetic, has been extensively used in perioperative period for several decades. A large amount of experimental studies have indicated that isoflurane exhibits neuroprotective properties when it is administrated before or after (pre-conditioning and post-conditioning) neurodegenerative diseases (e.g., hypoxic ischemia, stroke and trauma). Multiple mechanisms are involved in isoflurane induced neuroprotection, including activation of glycine and γ-aminobutyric acid receptors, antagonism of ionic channels and alteration of the function and activity of other cellular proteins. Although neuroprotection provided by isoflurane is observed in many animal studies, convincing evidence is lacking in human trials. Therefore, there is still a long way to go before translating its neuroprotective properties into clinical practice.

Ischemic conditioning of human heart muscle depends on opioid-receptor system

BACKGROUND

Despite progress in the invasive treatment of ischemic heart disease, the ability to limit ischemia-reperfusion (I/R) injury remains largely unrealized. Ischemic pre-conditioning (IPC) and post-conditioning (POC) induce the protective mechanisms of resistance against I/R injury. Stimulation of opioid receptors mimic the protective effect of IPC or POC in an animal models. We tested the hypothesis, that IPC and POC provide cardioprotection in opioid-dependent mechanism in human myocardium.

METHODS

Human atrial trabeculae were subjected to I/R injury. To achieve IPC, single hypoxia period preceded the applied lethal hypoxia, to achieve POC triple hypoxia periods followed lethal hypoxia. Naloxone was used at the onset of lethal hypoxia in IPC protocol, and at the time of re-oxygenation in POC protocol. Contractive function of the myocardium was assessed as maximal force of contraction (Amax), rate of rise of force of contraction (+dV/dT) and diastolic parameter - rate of decay of force of contraction (-dV/dT).

RESULTS

Co-application of naloxone with IPC or POC resulted in decrease of Amax, +dV/dT and -dV/dT during re-oxygenation period as compared to IPC or POC only.

CONCLUSIONS

Naloxone abrogates beneficial effect of IPC and POC. IPC and POC in humans provide cardioprotection in opioid receptor system dependent mechanism.

Anti-oxidative aspect of inhaled anesthetic gases against acute brain injury

Acute brain injury is a critical and emergent condition in clinical settings, which needs to be addressed urgently. Commonly acute brain injuries include traumatic brain injury, ischemic and hemorrhagic strokes. Oxidative stress is a key contributor to the subsequent injuries and impedes the reparative process after acute brain injury; therefore, facilitating an anti-oxidative approach is important in the care of those diseases. Readiness to deliver and permeability to blood brain barrier are essential for the use of this purpose. Inhaled anesthetic gases are a group of such agents. In this article, we discuss the anti-oxidative roles of anesthetic gases against acute brain injury.

Application of hyperbaric oxygen in liver transplantation

In recent years, hyperbaric oxygen (HBO) has been used in the treatment of a lot of diseases such as decompression sickness, arterial gas embolism, carbon dioxide poisoning, soft tissue infection, refractory osteomyelitis, and problematic wound, but little is known about its application in liver transplantation. Although several studies have been conducted to investigate the protective effects of HBO on liver transplantation and liver preservation, there are still some controversies on this issue, especially its immunomodulatory effect. In this short review, we briefly summarize the findings supporting the application of HBO during liver transplantation (including donors and recipients).

Adenosine Receptor Activation in the "Trigger" Limb of Remote Pre-Conditioning Mediates Human Endothelial Conditioning and Release of Circulating Cardioprotective Factor(s)

•

Pre-conditioning has emerged as a potentially powerful means of reducing ischemia-reperfusion injury.

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Several animal models have implicated adenosine in pre-conditioning pathways, but its role in human physiology is unknown.

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In human volunteers, the authors demonstrate that adenosine receptor activation in “trigger” tissue is an important step in initiating a pre-conditioning signal, but adenosine receptor blockade in “target” tissue does not block the protection afforded by pre-conditioning.

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The authors also demonstrate that pre-conditioning elaborates a transferrable cardioprotective factor(s) into the serum. This elaboration is prevented by adenosine receptor blockade but can be mirrored by the infusion of exogenous adenosine.

•

An improved understanding of the physiological effectors of pre-conditioning may allow for better targeted clinical studies of pre-conditioning and pre-conditioning mimetics in the future.

Remote ischemic pre-conditioning (rIPC) has emerged as a potential mechanism to reduce ischemia-reperfusion injury. Clinical data, however, have been mixed, and its physiological basis remains unclear, although it appears to involve release of circulating factor(s) and/or neural pathways. Here, the authors demonstrate that adenosine receptor activation is an important step in initiating human pre-conditioning; that pre-conditioning liberates circulating cardioprotective factor(s); and that exogenous adenosine infusion is able to recapitulate release of this factor. However, blockade of adenosine receptors in ischemic tissue does not block the protection afforded by pre-conditioning. These data have important implications for defining the physiology of human pre-conditioning and its translation to future clinical trials.

Akt: A Therapeutic Target in Hepatic Ischemia-Reperfusion Injury

BACKGROUND

Liver transplantation is the second most common transplant procedure in the United States. A leading cause of post-transplantation organ dysfunction is I/R injury. During I/R injury, the serine/threonine kinase Akt is activated, stimulating downstream mediators to promote cellular survival. Due to the cellular effects of Akt, therapeutic manipulation of the Akt pathway can help reduce cellular damage during hepatic I/R that occurs during liver transplantation.

OBJECTIVE

A full description of therapeutic options available that target Akt to reduce hepatic I/R injury has not been addressed within the literature. The purpose of this review is to illuminate advances in the manipulation of Akt that can be used to therapeutically target I/R injury in the liver.

METHODS

An in depth literature review was performed using the Scopus and PubMed databases. A total of 75 published articles were utilized for this manuscript. Terminology searched includes a combination of "hepatic ischemia/reperfusion injury", "Akt/PKB", "preconditioning" and "postconditioning."

RESULTS

Four principal methods that reduce I/R injury include hepatic pre- and postconditioning, pharmacological intervention and future miRNA/gene therapy. Discussed therapies used serum alanine aminotransferase levels, liver histology and phosphorylation of downstream mediators to confirm the Akt protective effect.

CONCLUSION

The activation of Akt from the reviewed therapies has resulted in predictable reduction in hepatocyte damage using the previously mentioned measurements. In a clinical setting, these therapies could potentially be used in combination to achieve better outcomes in hepatic transplant patients. Evidence supporting reduced I/R injury through Akt activation warrants further studies in human clinical trials.

Adaptive response to hypoxia and remote ischaemia pre-conditioning: a new hypoxia-inducible factors era in clinical medicine

Transient ischaemia leads to tolerance to subsequent protracted ischaemia. This 'ischaemia pre-conditioning' results from the induction of numerous protective genes, involved in cell metabolism, proliferation and survival, in antioxidant capacity, angiogenesis, vascular tone and erythropoiesis. Hypoxia-inducible factors (HIF) play a pivotal role in this transcriptional adaptive response. HIF prolyl hydroxylases (PHDs), serving as oxygen sensors, control HIFα degradation. HIF-mediated ischaemic pre-conditioning can be achieved with the administration of PHD inhibitors, with the attenuation of organ injury under various hypoxic and toxic insults. Clinical trials are currently under way, evaluating PHD inhibitors as inducers of erythropoietin. Once their safety is established, their potential use might be further tested in clinical trials in various forms of acute ischaemic and toxic organ damage. Repeated transient limb ischaemia was also found to attenuate ischaemic injury in remote organs. This 'remote ischaemic pre-conditioning' phenomenon (RIP) has been extensively studied recently in small clinical trials, preceding, or in parallel with an abrupt insult, such as myocardial infarction, cardiac surgery or radiocontrast administration. Initial results are promising, suggesting organ protection. Large-scale multi-centre studies are currently under way, evaluating the protective potential of RIP in cardiac surgery, in the management of myocardial infarction and in organ transplantation. The mechanisms of organ protection provided by RIP are poorly understood, but HIF seemingly play a role as well. Thus, Inhibition of HIF degradation with PHD inhibitors, as well as RIP (in part through HIF), might develop into novel clinical interventions in organ protection in the near future.

Attenuation of eccentric exercise-induced muscle damage conferred by maximal isometric contractions: a mini review

Although, beneficial in determined contexts, eccentric exercise-induced muscle damage (EIMD) might be unwanted during training regimens, competitions and daily activities. There are a vast number of studies investigating strategies to attenuate EIMD response after damaging exercise bouts. Many of them consist of performing exercises that induce EIMD, consuming supplements or using equipment that are not accessible for most people. It appears that performing maximal isometric contractions (ISOs) 2–4 days prior to damaging bouts promotes significant attenuation of EIMD symptoms that are not related to muscle function. It has been shown that the volume of ISOs, muscle length in which they are performed, and interval between them and the damaging bout influence the magnitude of this protection. In addition, it appears that this protection is not long-lived, lasting no longer than 4 days. Although no particular mechanisms for these adaptations were identified, professionals should consider applying this non-damaging stimulus before submitting their patients to unaccustomed exercised. However, it seems not to be the best option for athletes or relatively trained individuals. Future, studies should focus on establishing if ISOs protect other populations (i.e., trained individuals) or muscle groups (i.e., knee extensors) against EIMD, as well as investigate different mechanisms for ISO-induced protection.

The role of HIFs in ischemia-reperfusion injury

The reduction or cessation of the blood supply to an organ results in tissue ischemia. Ischemia can cause significant tissue damage, and is observed as a result of a thrombosis, as part of a disease process, and during surgery. However, the restoration of the blood supply often causes more damage to the tissue than the ischemic episode itself. Research is therefore focused on identifying the cellular pathways involved in the protection of organs from the damage incurred by this process of ischemia reperfusion (I/R). The hypoxia-inducible factors (HIFs) are a family of heterodimeric transcription factors that are stabilized during ischemia. The genes that are expressed downstream of HIF activity enhance oxygen-independent ATP generation, cell survival, and angiogenesis, amongst other phenotypes. They are, therefore, important factors in the protection of tissues from I/R injury. Interestingly, a number of the mechanisms already known to induce organ protection against I/R injury, including preconditioning, postconditioning, and activation of signaling pathways such as adenosine receptor signaling, converge on the HIF system. This review describes the evidence for HIFs playing a role in I/R protection mediated by these factors, highlights areas that require further study, and discuss whether HIFs themselves are good therapeutic targets for protecting tissues from I/R injury.

Preconditioning with hyperbaric oxygen in pancreaticoduodenectomy: a randomized double-blind pilot study

In a prospective randomized double-blind study, we evaluated the post-operative biological and clinical effects of a single preoperative hyperbaric-treatment the day before surgery for pancreatic ductal adenocarcinoma.

PATIENTS AND METHODS

Twenty one patients were randomized and divided into two groups: group-A (10 patients, 48%) were exposed to a HyperBaric Oxygen (HBO) session the day before intervention [Pre-Intervention Day (PID)], group-B (11 patients, 52%) breathed air for 40 min in a hyperbaric chamber pressurized to 1.15 ATA (placebo group). For all patients blood samples were obtained before HBO treatment or the placebo procedure (T0); at the end of HBO session or placebo procedure (T1); on the first post-operative day (POD)(T2) and on seventh POD(T3) day, measuring interleukin (IL)-1, IL-6, IL-8, IL-10, IL-12 and TNF-α, recording postoperative pancreatic fistula (POPF), biliary-fistula, fever, intra-abdominal abscess, bleeding, pulmonary complications, delayed gastric emptying and requirement for post-operative antibiotics. The results of the present pilot study suggest that a single preoperative hyperbaric oxygen treatment on the day before surgery may reduce the complication rate in pancreatic resection.

Comparison of the Nanostructure and Mechanical Performance of Highly Exfoliated Epoxy-Clay Nanocomposites Prepared by Three Different Protocols

Three different protocols for the preparation of polymer layered silicate nanocomposites based upon a tri-functional epoxy resin, triglycidyl para-amino phenol (TGAP), have been compared in respect of the cure kinetics, the nanostructure and their mechanical properties. The three preparation procedures involve 2 wt% and 5 wt% of organically modified montmorillonite (MMT), and are: isothermal cure at selected temperatures; pre-conditioning of the resin-clay mixture before isothermal cure; incorporation of an initiator of cationic homopolymerisation, a boron tri-fluoride methyl amine complex, BF₃·MEA, within the clay galleries. It was found that features of the cure kinetics and of the nanostructure correlate with the measured impact strength of the cured nanocomposites, which increases as the degree of exfoliation of the MMT is improved. The best protocol for toughening the TGAP/MMT nanocomposites is by the incorporation of 1 wt% BF₃·MEA into the clay galleries of nanocomposites containing 2 wt% MMT.

Subcellular expression and neuroprotective effects of SK channels in human dopaminergic neurons

Small-conductance Ca(2+)-activated K(+) channel activation is an emerging therapeutic approach for treatment of neurological diseases, including stroke, amyotrophic lateral sclerosis and schizophrenia. Our previous studies showed that activation of SK channels exerted neuroprotective effects through inhibition of NMDAR-mediated excitotoxicity. In this study, we tested the therapeutic potential of SK channel activation of NS309 (25 μM) in cultured human postmitotic dopaminergic neurons in vitro conditionally immortalized and differentiated from human fetal mesencephalic cells. Quantitative RT-PCR and western blotting analysis showed that differentiated dopaminergic neurons expressed low levels of SK2 channels and high levels of SK1 and SK3 channels. Further, protein analysis of subcellular fractions revealed expression of SK2 channel subtype in mitochondrial-enriched fraction. Mitochondrial complex I inhibitor rotenone (0.5 μM) disrupted the dendritic network of human dopaminergic neurons and induced neuronal death. SK channel activation reduced mitochondrial membrane potential, while it preserved the dendritic network, cell viability and ATP levels after rotenone challenge. Mitochondrial dysfunction and delayed dopaminergic cell death were prevented by increasing and/or stabilizing SK channel activity. Overall, our findings show that activation of SK channels provides protective effects in human dopaminergic neurons, likely via activation of both membrane and mitochondrial SK channels. Thus, SK channels are promising therapeutic targets for neurodegenerative disorders such as Parkinson's disease, where dopaminergic cell loss is associated with progression of the disease.

Isoflurane provides neuroprotection in neonatal hypoxic ischemic brain injury

Isoflurane is a volatile anesthetic that is widely used clinically as an inhalational anesthetic. In recent years, several studies have indicated that isoflurane has neuroprotective properties. This has led to the beneficial effects of isoflurane being analyzed in both cell culture and animal models, including various models of brain injury. Neonatal hypoxia ischemia may be characterized as injury that occurs in the immature brain, resulting in delayed cell death via excitotoxicity and oxidative stress. These adverse events in the developing brain often lead to detrimental neurological defects in the future. Currently, there are no well-established effective therapies for neonatal hypoxia ischemia. In line with this, isoflurane, which displays neuroprotective properties in several paradigms and has been shown to improve neurological deficits caused by brain injuries, has the capability to be an extremely relevant clinical therapy for the resolution of deficits concomitant with neonatal hypoxic ischemic brain injuries. This review therefore seeks to explore and analyze the current information on isoflurane, looking at general isoflurane anesthetic properties, and the protection it confers in different animal models, focusing particularly on neuroprotection as shown in studies with neonatal hypoxic ischemic brain injury.

Hypoxia-based strategies for angiogenic induction: the dawn of a new era for ischemia therapy and tissue regeneration

Therapeutic angiogenesis promises to aid the healing and regeneration of tissues suffering from a compromised vascular supply. Ischaemia therapy has so far primarily focused on delivering isolated angiogenic growth factors. The limited success of these strategies in clinical trials, however, is increasingly forcing researchers to recognize the difficulties associated with trying to mimic the angiogenic process, due to its natural complexity. Instead, a new school of thought is gradually emerging, focusing on how to induce angiogenesis at its onset, by utilizing hypoxia, the primary angiogenic stimulus in physiological, as well pathological states. This shift in therapeutic approach is underlined by the realization of the importance of depressed HIF-1 α-mediated gene programming in non-healing ischemic tissues, which could explain their apparent habituation to chronic hypoxic stress and the limited capacity to generate adaptive angiogenesis. Hypoxia-based strategies, then effectively aim to override the habituated angiogenic cellular response, re-start the regenerative process and drive it to completion. Here we make a distinction between those strategies that utilize hypoxia in vitro as a preconditioning tool to optimize the angiogenic potential of tissue/cells before transplantation, vs. strategies that aim to induce hypoxia-induced signaling in vivo, directly, through pharmacological means or gene transfer. We then discuss possible future directions for the field, as it moves into the phase of clinical trials.

Mesenchymal stem cells conditioned with glucose depletion augments their ability to repair-infarcted myocardium

Mesenchymal stem cells (MSCs) are an attractive candidate for autologous cell therapy, but their ability to repair damaged myocardium is severely compromised with advanced age. Development of viable autologous cell therapy for treatment of heart failure in the elderly requires the need to address MSC ageing. In this study, MSCs from young (2 months) and aged (24 months) C57BL/6 mice were characterized for gene expression of IGF-1, FGF-2, VEGF, SIRT-1, AKT, p16(INK4a) , p21 and p53 along with measurements of population doubling (PD), superoxide dismutase (SOD) activity and apoptosis. Aged MSCs displayed senescent features compared with cells isolated from young animals and therefore were pre-conditioned with glucose depletion to enhance age affected function. Pre-conditioning of aged MSCs led to an increase in expression of IGF-1, AKT and SIRT-1 concomitant with enhanced viability, proliferation and delayed senescence. To determine the myocardial repair capability of pre-conditioned aged MSCs, myocardial infarction (MI) was induced in 24 months old C57BL/6 wild type mice and GFP expressing untreated and pre-conditioned aged MSCs were transplanted. Hearts transplanted with pre-conditioned aged MSCs showed increased expression of paracrine factors, such as IGF-1, FGF-2, VEGF and SDF-1α. This was associated with significantly improved cardiac performance as measured by dp/dt(max), dp/dt(min), LVEDP and LVDP, declined left ventricle (LV) fibrosis and apoptosis as measured by Masson's Trichrome and TUNEL assays, respectively, after 30 days of transplantation. In conclusion, pre-conditioning of aged MSCs with glucose depletion can enhance proliferation, delay senescence and restore the ability of aged cells to repair senescent infarcted myocardium.