The ARRIVE guidelines 2.0: updated guidelines for reporting animal research

SEW2871 attenuates myocyte necroptosis in heart failure through inhibition of oxidative stress and inflammatory cytokines

BACKGROUND AND PURPOSE

Sphingosine-1-phosphate (S1P)/S1P receptor signalling exerts cardioprotective effects. However, the effect of the selective S1P1 receptor agonist SEW2871 on myocyte necroptosis in heart failure and the underlying mechanisms are unknown. In the present study, we tested the hypothesis that SEW2871 attenuates myocyte necroptosis in heart failure through inhibition of oxidative stress and inflammatory cytokines.

EXPERIMENTAL APPROACH

Eight-week-old male C57BL/6J mice underwent myocardial infarction (MI) or sham operation. The animals were randomized to receive SEW2871 (5 mg·kg-1·day-1, i.p) or placebo for 4 weeks.

KEY RESULTS

MI mice exhibited the increases in left ventricular (LV) end-diastolic dimension, LV end-systolic dimension, LV mass and lung weight and a decrease in LV ejection fraction, indicating LV dilation, LV systolic dysfunction and lung congestion, and these alterations were attenuated by the SEW2871 treatment. Myocardial expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress, inflammatory cytokines tumour necrosis factor-α (TNF-α), interleukin-1β and interleukin-6, and phosphorylated RIPK1 (p-RIPK1), p-RIPK3 and p-MLKL, reflective of their respective kinase activities, markers of necroptosis, was markedly increased in the MI placebo group, and the increase was abolished by the SEW2871 treatment. Similarly, intracellular levels of reactive oxygen species, inflammatory cytokines, p-RIPK1, p-RIPK3 and p-MLKL protein expression were increased in H9C2 cardiomyocytes under mimic ischaemia and the increases were prevented by the SEW2871 treatment.

CONCLUSION AND IMPLICATIONS

The selective S1P1 receptor agonist SEW2871 attenuates myocyte necroptosis through inhibition of oxidative stress and inflammatory cytokines, leading to improvement of LV remodelling and function in heart failure.

Gusongan capsule enhances osteogenic differentiation to mitigate bone loss in ovariectomized rats via the TLR2/NF-κB pathway

BACKGROUND

Osteoporosis (OP) is a metabolic bone disease characterized by reduced bone mass and impaired bone microstructure, leading to an increased risk of fractures. In this context, the Gusongan (GSA) capsule has gained recognition for its osteogenic potential.

PURPOSE

This study sought to examine the therapeutic effects of GSA capsule on OP and to elucidate the molecular mechanisms underpinning its osteoprotective properties.

METHODS

An OP model was established in female Sprague-Dawley rats through bilateral ovariectomy (OVX), followed by gavage administration of varying doses of GSA capsule. The study included the control, OVX model, and positive control (alendronate) groups. Bone mineral density (BMD) and serum biomarkers of rats were analyzed using micro-computed tomography (micro-CT) and enzyme-linked immunosorbent assay (ELISA). RNA sequencing (RNA-seq)- and network pharmacology-based analyses were conducted to identify potential molecular targets. Additionally, in vitro experiments were performed to evaluate the impacts of GSA capsule on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and the TLR2/NF-κB pathway.

RESULTS

Micro-CT analysis demonstrated that GSA capsule treatment markedly improved BMD, trabecular number (Tb.N), and bone volume/total volume (BV/TV), while reducing trabecular separation (Tb.Sp) (p< 0.05). ELISA results further revealed that GSA capsule diminished serum levels of bone Gla protein (BGP), bone alkaline phosphatase (BALP), and tartrate-resistant acid phosphatase (TRACP) in OVX rats (p< 0.05), suggesting an inhibitory effect on bone resorption and turnover. RNA-seq- and network pharmacology-based analyses highlighted the downregulation of key factors in the TLR2/NF-κB pathway in BMSCs following GSA capsule treatment. Furthermore, GSA capsule enhanced BALP activity and mineralized nodule formation in BMSCs (p< 0.05). In vitro investigations corroborated that GSA capsule downregulated TLR2 and NF-κB p65 levels and fostered the expression of osteogenic genes, including COL1A1, RUNX2, and OPN (p< 0.05).

CONCLUSION

This study highlighted that GSA capsule attenuated inflammation and augmented osteogenic differentiation of BMSCs by targeting the TLR2/NF-κB pathway. These molecular mechanisms contributed to enhanced BMD and bone microarchitecture in OVX rats, suggesting the therapeutic potential of GSA capsule in OP management.

Mitochondrial haplotype and sex modulate responses to endurance exercise training

Heterogeneity in the response to exercise training is widely demonstrated in the literature. Although the variability in exercise acclimation is not entirely understood, a large portion of exercise response variability is attributable to genetic heritability potentially due to inherited maternal mitochondrial characteristics. Humans exhibit a heterogenous genome and mitochondrial haplotype; however much of the preclinical research proposed to investigate molecular transducers of exercise has been implemented using mouse models that lack mitochondrial and nuclear genomic diversity. Leveraging a novel rat model of heterogeneous genome, OKC-HET rats, we investigated the impact of mitochondrial (mt) haplotype on exercise training. We hypothesized that rats with divergent mitochondrial genomes will respond differently to endurance exercise training. OKC-HET rats aged 18-19 months old were subjected to 8 weeks of voluntary wheel running as their endurance exercise training programme. We found mt haplotype-specific effects on responses to endurance exercise and motor co-ordination, which were consistent with mitochondrial bioenergetics and markers of oxidative stress. Mitochondrial copy number and the expression of mitochondrial proteins were similar between the two mt haplotypes, suggesting intrinsic alterations of mitochondrial functions by the two distinct mitochondrial genomes. Motor co-ordination and fragmentation of acetylcholine receptors were also affected by mitochondrial haplotype. The mt haplotype effects on training responses were specific to biological sex also. Collectively we report that mitochondrial haplotype significantly affects responses to endurance exercise in a sex-specific manner. KEY POINTS: Mitochondrial haplotype affects the responses to endurance exercise. Sex modulates the effects of mitochondrial haplotype in the responses to endurance training. Mitochondrial DNA (mtDNA) deletion frequency increases following endurance exercise. mtDNA deletion frequency is higher in males than females after endurance exercise in OKC-HET rats.

Cardiopulmonary remodeling following repetitive acute pulmonary emboli and inhibition of endogenous fibrinolysis in a porcine model

BACKGROUND

The underlying pathophysiology of chronic thromboembolic pulmonary disease (CTEPD) with or without sustained pulmonary hypertension (pH) remains unclear, but repetitive pulmonary emboli (PE) and impaired fibrinolysis are known risk factors. We hypothesized that repetitive PE and inhibition of endogenous fibrinolysis would induce CTEPD with PH (CTEPH).

METHODS

Twenty-four Danish female slaughter pigs of ∼60 kg (4 groups of 6 pigs) were included in the study. Pigs received either autologous PE (PE group), PE plus tranexamic acid (PE + TXA), repetitive PE (day 0, 3, 7, and 10) plus tranexamic acid (REP PE + TXA), or saline infusion (SHAM). Pigs were evaluated at baseline and on day 30 using computed tomography pulmonary angiography (CTPA), invasive hemodynamics, and tissue samples.

RESULTS

CTPA showed increased pulmonary obstruction score on day 30 in REP PE + TXA group compared to remaining groups (0 ± 0 SHAM vs 31 ± 21 PE vs 42 ± 12 PE + TXA vs 69 ± 17 % REP PE + TXA, P = 0.004). Mean pulmonary arterial pressure was higher in REP PE + TXA group on day 30 than remaining groups (12 ± 2 SHAM vs 13 ± 1 PE vs 12 ± 2 PE + TXA vs 16 ± 2 mmHg REP PE + TXA, P = 0.002) yet none of the groups developed PH and right ventricular function was normalized after 30 days. In histological samples, we found chronic thromboembolic lesions with organized fibrotic thrombi, revascularization, and neointima formation, but no microvascular remodeling.

CONCLUSIONS

Autologous repetitive PE and inhibited fibrinolysis caused chronic thrombi without PH in a porcine model. Our findings suggest that a repetitive PE and impaired endogenous fibrinolysis alone are insufficient to develop CTEPH.

TRANSLATIONAL ASPECT

This porcine model using autologous pulmonary emboli presents a realistic large animal model of chronic thromboembolic pulmonary disease particularly suitable to further investigate the vascular remodeling after acute PE. Future research should examine the role of inflammation, endothelial dysfunction and angiogenesis-driven clot resolution to improve understanding of the pathophysiological mechanisms.

Platelet-Derived PDGF-A Disrupts Blood-Brain Barrier Integrity in Ischemic Stroke

BACKGROUND

Ischemic stroke (IS) is a prevalent cause of death and disability worldwide. Cerebral ischemia induces profound changes at the blood-brain barrier, which lead to a remarkable increase in paracellular permeability, worsening outcomes. Platelets are well known for safeguarding vascular integrity and the prevention of bleeding complications. On the other hand, platelet activation contributes to infarct progression in the context of IS. The manifold, context-dependent roles of platelets, however, have not yet been resolved.

METHODS

IS was mimicked by transient middle cerebral artery occlusion in wild-type, transgenic, or treated mice, and vascular leakage was assessed by intravital 2-photon microscopy, as well as Western blotting and immunohistochemistry. Barrier property of primary murine brain microvascular endothelial cells was measured as transendothelial electrical resistance of cellular monolayers in response to platelet releasate or recombinant proteins.

RESULTS

IS induces blood-brain barrier breakdown characterized by time-dependent leakage of albumin in the brain parenchyma. We could show that local platelet activation triggers the release of PDGF (platelet-derived growth factor)-A from α-granules, which induces the loss of brain endothelial cell layer integrity. This translates to a comprised vascular integrity in vivo. In the absence of α-granule content (Nbeal2-/-) or pharmacological blockade of PDGF, no disruption of the endothelial layer or vascular leakage was observed.

CONCLUSIONS

PDGF-A released from platelets impairs blood-brain barrier integrity, resulting in detrimental vascular leakage and infarct progression. These findings provide important insights on the pivotal role of platelets in IS further elucidating the mechanisms of thromboinflammation in the brain.

An NRF2/β3-Adrenoreceptor Axis Drives a Sustained Antioxidant and Metabolic Rewiring Through the Pentose-Phosphate Pathway to Alleviate Cardiac Stress

BACKGROUND

Cardiac β3-adrenergic receptors (ARs) are upregulated in diseased hearts and mediate antithetic effects to those of β1AR and β2AR. β3AR agonists were recently shown to protect against myocardial remodeling in preclinical studies and to improve systolic function in patients with severe heart failure. However, the underlying mechanisms remain elusive.

METHODS

To dissect functional, transcriptional, and metabolic effects, hearts and isolated ventricular myocytes from mice harboring a moderate, cardiac-specific expression of a human ADRB3 transgene (β3AR-Tg) and subjected to transverse aortic constriction were assessed with echocardiography, RNA sequencing, positron emission tomography scan, metabolomics, and metabolic flux analysis. Subsequently, signaling and metabolic pathways were further investigated in vivo in β3AR-Tg and ex vivo in neonatal rat ventricular myocytes adenovirally infected to express β3AR and subjected to neurohormonal stress. These results were complemented with an analysis of single-nucleus RNA-sequencing data from human cardiac myocytes from patients with heart failure.

RESULTS

Compared with wild-type littermates, β3AR-Tg mice were protected from hypertrophy after transaortic constriction, and systolic function was preserved. β3AR-expressing hearts displayed enhanced myocardial glucose uptake under stress in the absence of increased lactate levels. Instead, metabolomic and metabolic flux analyses in stressed hearts revealed an increase in intermediates of the pentose-phosphate pathway in β3AR-Tg, an alternative route of glucose utilization, paralleled with increased transcript levels of NADPH-producing and rate-limiting enzymes of the pentose-phosphate pathway, without fueling the hexosamine metabolism. The ensuing increased content of NADPH and of reduced glutathione decreased myocyte oxidant stress, whereas downstream oxidative metabolism assessed by oxygen consumption was preserved with higher glucose oxidation in β3AR-Tg mice after transaortic constriction compared with wild type, together with increased mitochondrial biogenesis. Unbiased transcriptomics and pathway analysis identified NRF2 (NFE2L2) as an upstream transcription factor that was functionally verified in vivo and in β3AR-expressing cardiac myocytes, where its translocation and nuclear activity were dependent on β3AR activation of nitric oxide synthase and nitric oxide production through S-nitrosation of the NRF2-negative regulator Keap1.

CONCLUSIONS

Moderate expression of cardiac β3AR, at levels observed in human cardiac myocardium, exerts metabolic and antioxidant effects through activation of the pentose-phosphate pathway and NRF2 pathway through S-nitrosation of Keap1, thereby preserving myocardial oxidative metabolism, function, and integrity under pathophysiological stress.

Reporting preclinical gene therapy studies in the field of Niemann-Pick type C disease according to the ARRIVE guidelines

The lack of essential information when reporting animal studies causing lower reproducibility has been stressed for decades. The ARRIVE (Animal Research: Reporting of In Vivo Experiments) guidelines were first published in 2010, to improve reporting of animal research, making in vivo studies more transparent thereby improving the scientific quality. Regardless of an endorsement from the scientific community, there is still a continuous need to improve animal research reporting, which unfortunately also is the case in the field of Niemann-Pick type C disease (NPC). NPC is a lipid storage disorder, caused by mutations in either the Npc1 or Npc2 gene. Despite years of research, no cure for this fatal disease exists. In 2020, an updated version of the ARRIVE guidelines (ARRIVE 2.0), was published, describing the ten most essential elements to be included when reporting pre-clinical studies. Here we systematically reviewed the compliance with the ARRIVE guidelines using the "ARRIVE Essential 10" checklist in a series of pre-clinical studies investigating gene therapy as a treatment strategy for NPC. None of the reviewed papers fulfilled the ARRIVE 2.0 guidelines. Information regarding sample size, randomization, blinding, and statistical methodology was lacking. Hopefully, the newly updated ARRIVE guidelines will aid researchers in planning and publishing in vivo experiments in the future. More awareness of the importance of including these essential items is needed, both from editors, reviewers and researchers, for complete endorsement of the ARRIVE guidelines in the scientific community.

P2Y12 signaling in muscle satellite cells contributes to masseter muscle contraction-induced pain

The mechanism behind masseter muscle pain, a major symptom of temporomandibular disorder (TMD), has remained poorly understood. Previous report indicates that adenosine triphosphate (ATP) is involved in the masseter muscle pain development, but the role of its hydrolysis product, adenosine diphosphate (ADP), remains uncertain. Consequently, this study aimed to elucidate the ADP role derived from the sustained masseter muscle contraction in the masseter muscle pain development. The right masseter muscle was electrically stimulated daily by placing electrodes on the muscle fascia, inducing strong contraction and mechanical allodynia. This led to an increment of the ATP release from the masseter muscle and a consequent increase in ADP produced by the hydrolysis of ATP. The mechanical allodynia was suppressed by intramuscular P2Y12 receptor antagonism and tumor necrosis factor alpha (TNF-α) inhibition. Additionally, muscle satellite cells expressed P2Y12 receptors, and the increase in amount of TNF-α released from these cells due to sustained contraction of the masseter muscle was suppressed by intramuscular P2Y12 receptor antagonism. These findings suggest that sustained masseter muscle contraction increases ADP levels within the muscle; this ADP, produced by the hydrolysis of ATP, promotes the release of TNF-α via P2Y12 receptors. The TNF-α signaling is likely to enhance the excitability of primary neurons projecting to the masseter muscle, thereby inducing masseter muscle pain. Therefore, it is plausible that TNF-α-induced nociceptive neuronal hyperexcitability through enhanced ADP signaling via P2Y12 receptors in satellite cells could be a candidate for therapeutic intervention for masseter muscle pain, a major symptom of TMD. PERSPECTIVE: Sustained masseter muscle contraction in rats induced mechanical allodynia and increased the amount of ADP within the muscle. Muscle satellite cells expressed P2Y12 receptors, and ADP-P2Y12 signaling increased the TNF-α release from these cells. TNF-α signaling enhanced the primary neuronal excitability, inducing masseter muscle pain.

Human Mesenchymal Stem Cell-Derived Exosomes as Engineering Vehicles of Daunorubicin for Targeted c-Mpl+ AML Therapy

Background

Acute myeloid leukemia (AML) is a highly heterogeneous disease with poor therapeutic outcomes and overall prognosis, particularly in c-Mpl+ AML. c-Mpl, a proto-oncogene, is expressed at significantly higher levels in AML compared to normal human tissue cells. This study aimed to develop a type of targeted exosomes (Exos) capable of delivering anticancer drugs directly to c-Mpl+ AML cells.

Methods

Human umbilical cord mesenchymal stem cells (hUCMSCs) were isolated as the source of Exos. Fusion CD63 proteins with varying numbers of thrombopoietin (TPO)-mimic peptides, designed to target c-Mpl, were bioengineered to be expressed on the membranes of hUCMSCs and their derived Exos. The targeting capability of the fusion proteins was assessed using the DUAL membrane system, fluorescence resonance energy transfer efficiency, and endocytosis assays. After encapsulating the anticancer drug daunorubicin (DNR), these targeted Exos were evaluated for their ability to eliminate c-Mpl+ AML cells. Safety and efficacy were further tested in a mouse AML model.

Results

Our findings showed that the engineered hUCMSCs-derived Exos demonstrated excellent targeting ability to c-Mpl and a strong propensity for endocytic uptake by c-Mpl+ AML cells. Among the engineered Exos, those with the fusion protein containing three TPO-mimic peptides (CD63-mTPO3), named as m3Exos, exhibited the highest binding affinity for c-Mpl. When loaded with DNR, these engineered Exos (m3Exos@DNR) effectively eliminated c-Mpl+ AML cells in both in vitro and in vivo experiments. Furthermore, safety assessments revealed that therapy-related toxicities were within acceptable limits and associated with manageable side effects.

Conclusion

In summary, our results suggest engineered Exos as a highly effective targeted drug delivery vehicle for eliminating c-Mpl+ AML cells while maintaining a favorable safety profile. These findings also provide valuable insights for developing therapeutic strategies for AML and other tumors characterized by specific membrane protein expression.

Deletion of microsomal epoxide hydrolase gene leads to increased density in cerebral vasculature and enhances cerebral blood flow in mice

Microsomal epoxide hydrolase (mEH), first identified as detoxifying enzyme, can hydrolyze epoxyeicosatrienoic acids (EETs) to less active diols (DHETs). EETs are potent vasodilatory and pro-angiogenic lipids, also implicated in neurovascular coupling. In mouse brain, mEH is strongly expressed in vascular and perivascular cells in contrast to the related soluble epoxide hydrolase (sEH), predominantly found in astrocytes. While sEH inhibition in stroke has demonstrated neuroprotective effects and increases cerebral blood flow (CBF), data regarding the role of mEH in brain are scarce. Here, we explored the function of mEH in cerebral vasculature by comparing mEH-KO, sEH-KO and WT mice. Basal cerebral volume (CBV0) was significantly higher in various mEH-KO brain areas compared to WT and sEH-KO. In line, quantification of cerebral vasculature in cortex and thalamus revealed a higher capillary density in mEH-KO, but not in sEH-KO brain. Whisker-stimulated CBF changes were by factor two higher in both mEH-KO and sEH-KO. In acutely isolated cerebral endothelial cells the loss of mEH, but not of sEH, augmented total EET levels and decreased the DHET:EET ratio. Collectively, these data suggest an important function of mEH in the regulation of cerebral vasculature and activity-modulated CBF, presumably by controlling local levels of endothelial-derived EETs.

Correction of metal artefacts around orthodontic mini-implants - a micro-CT study in the rat tail model

Micro-CT enables volumetric analysis of peri-implant tissue, but grey value alterations due to metal artefacts can impair analyses. This study aimed to assess to which extent peri-implant grey values are affected by metal artefacts at increasing distance to the implant, and whether mathematical correction is possible. In nine rats, two Ti6Al4V orthodontic mini-implants (OMIs), 0.8 mm in diameter and 3.0 mm in length, were placed in a single tail vertebra. Micro-CT scans were performed before (T0) and after (T1) careful removal of the OMIs. Consecutive micro-CT scans were registered and differences in local grey values were computed at increasing distance to the implant (10.4 μm to 405.6 μm). Correction coefficient (CC) computation was performed using a smoothing spline fit, with the distance to the implant and the grey value difference as independent and dependent variable, respectively. To validate the effectiveness of the CC, the amount of calcified bone volume per total volume (BV/TV) was assessed within a standardized volume of interest (VOI) reaching up to 1 mm around the OMIs before and after the application of CC, and the T1-T0 differences between corrected and uncorrected scans were compared using the Wilcoxon signed-rank test. The grey value difference between uncorrected T0 and T1 scans was low in proximity to the implant (32.7%±6.11%) and improved at a distance of at least 100 μm (93.4%±4.46%). CC computation revealed a satisfactory fit (R2 = 0.989, RMSE = 0.031) and the difference in grey values was significantly lower after correction (p < 0.001). Most VOIs showed significant improvement, though overcorrection was observed in a few cases. Within the limitations of the study, metal artefacts decreased with increasing distance to the OMIs, and significant improvement was possible using the CC.

Effects of Melatonin on H2O2-Induced Oxidative Damage of the Granulosa Cells in Hen Ovarian Follicles

BACKGROUND

The egg-laying performance of hens is primarily regulated by ovarian follicle growth and development; these follicles are susceptible to oxidative damage caused by excessive reactive oxygen species (ROS). Oxidative damage can lead to follicular atresia and impaired reproductive performance. Melatonin (MT), a known endogenous antioxidant, plays a role in regulating oxidative damage, but its precise mechanisms in mitigating H2O2-induced oxidative damage via mitophagy regulation in granulosa cells remain unclear.

METHODS

An in vitro oxidative damage model was established by determining the optimal H2O2 concentration using CCK-8 fluorescence quantification. The optimal MT concentration was identified through fluorescence quantification and catalase (CAT) activity assays. The protective effects of MT against H2O2-induced oxidative damage in follicular granulosa cells were investigated using flow cytometry, Western blotting, ELISA, and quantitative fluorescence analysis.

RESULTS

An in vitro oxidative damage model was established using H2O2-induced granulosa cells, characterized by P53 and LC3-II upregulation and LC3-I and BCL-2 downregulation. The optimal MT concentration for reducing cellular injury was determined. MT co-treatment enhanced CAT, GSH, and SOD activities, decreased LC3-II/LC3-I conversion, and increased P62 expression. Furthermore, MT reduced autophagic vesicle formation and restored mitochondrial membrane potential, demonstrating its protective effect against H2O2-induced oxidative damage.

CONCLUSIONS

Melatonin alleviates H2O2-induced oxidative damage in chicken follicular granulosa cells by modulating antioxidant defense, autophagy, and mitochondrial function. These findings provide newer insights to our understanding of the regulatory mechanisms underlying the alleviation of the H2O2-induced oxidative damage in granulosa cells during ovarian follicle development in chickens.

Role of trigeminal ganglion satellite glial cells in masseter muscle pain hypersensitivity

OBJECTIVES

The underlying mechanism of masseter muscle pain hypersensitivity by sustained masseter muscle contraction (SMMC) is not well understood. This study aimed to examine whether the activation of satellite glial cells in the trigeminal ganglion (TG) contributes to masseter muscle pain hypersensitivity induced by SMMC.

METHODS

Electrodes were placed on the masseter muscle fascia of rats to induce strong contractions, by daily electrical stimulation. Pain sensitivity in the masseter muscle was measured and the activation level of satellite glial cells in the TG was examined. The localization of P2Y12 and the effects of P2Y12 receptor inhibition on SMMC-induced pain hypersensitivity were evaluated. The amount of tumor necrosis factor alpha (TNF-α) and TNF-α receptor localization were determined in the TG.

RESULTS

SMMC induced masseter muscle pain hypersensitivity and activation of satellite glial cells. P2Y12 receptors were expressed in satellite glial cells and masseter muscle pain hypersensitivity was suppressed by intra-TG P2Y12 receptor antagonism. TG neurons innervating the sustained-contracted masseter muscle expressed TNF-α receptor and SMMC increased TNF-α levels in TG.

CONCLUSION

SMMC-induced activation of satellite glial cells though the P2Y12 receptor signaling may contribute to masseter muscle pain hypersensitivity via the TNF-α signaling pathway.

Pulmonary Artery Pulsatility Index in Acute and Chronic Pulmonary Embolism

Background and Objectives: The pulmonary artery pulsatility index (PAPi) is an emerging marker of right ventricular (RV) injury but has not been well investigated in acute pulmonary embolism (PE) or chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to investigate its discriminatory capabilities and ability to detect therapeutic effects in acute PE and CTEPH. Materials and Methods: This was a secondary analysis of data from both experimental studies of autologous PE and human studies of acute PE and CTEPH. PAPi was calculated and compared in (1) PE versus sham and (2) before and after interventions aimed at reducing RV afterload in PE and CTEPH. The correlations between PAPi, cardiac output, and RV to pulmonary artery coupling were investigated. Results: PAPi did not differ between animals with acute PE versus sham, nor was it affected by clot burden (p = 0.673) or at a 30-day follow-up (p = 0.242). Pulmonary vasodilatation with oxygen was associated with a reduction in PAPi (4.9 [3.7-7.8] vs. 4.0 [3.2-5.6], p = 0.016), whereas positive inotropes increased PAPi in the experimental PE. In humans, PAPi did not change consistently with interventions. Balloon pulmonary angioplasty did not significantly increase PAPi (6.5 [4.3-10.7] vs. 9.8 [6.8-14.2], p = 0.1) in patients with CTEPH, and a non-significant reduction in PAPi (4.3 ± 1.6 vs. 3.3 ± 1.2, p = 0.074) was observed in patients with acute PE who received sildenafil. PAPi did not correlate well with cardiac output or measures of RV to pulmonary artery coupling in either species. Conclusions: PAPi did not detect acute, experimental PE or changes as a result of therapeutic interventions in patients with hemodynamically stable acute PE or CTEPH. However, it did change with pharmacological interventions in the experimental PE. Further research should establish its utility in detecting and monitoring RV injury in different clinical phenotypes of acute PE and CTEPH.

Novel cisplatin-magnetoliposome complex shows enhanced antitumor activity via Hyperthermia

There are several methods to improve cancer patient survival rates by inducing hyperthermia in tumor tissues, which involves raising their temperature above 41 °C. These methods utilize different energy sources to deliver heat to the target region, including light, microwaves or radiofrequency electromagnetic fields. We have developed a new, magnetically responsive nanocarrier, consisting of liposomes loaded with magnetic nanoparticles and cis-diamminedichloroplatinum (II) (CDDP), commonly known as Cisplatin. The resulting magnetoliposome (ML) is rapidly internalized by lung and pancreas tumor cell lines, stored in intracellular vesicles, and capable of inducing hyperthermia under magnetic fields. The ML has no significant toxicity both in vitro and in vivo and, most importantly, enhances cell death by apoptosis after magnetic hyperthermia. Remarkably, mice bearing induced lung tumors, treated with CDDP-loaded nanocarriers and subjected to an applied electromagnetic field, showed an improved survival rate over those treated with either soluble CDDP or hyperthermia alone. Therefore, our approach of magnetic hyperthermia plus CDDP-ML significantly enhances in vitro cell death and in vivo survival of treated animals.

Slow rewarming after hypothermia does not ameliorate white matter injury after hypoxia-ischemia in near-term fetal sheep

BACKGROUND

The optimal rate to rewarm infants after therapeutic hypothermia is unclear. In this study we examined whether slow rewarming after 72 h of hypothermia would attenuate white matter injury.

METHODS

Near-term fetal sheep received sham occlusion (n = 8) or cerebral ischemia for 30 min, followed by normothermia (n = 7) or hypothermia from 3-72 h, with either spontaneous fast rewarming (n = 8) within 1 h, or slow rewarming at ~0.5 °C/h (n = 8) over 10 h. Fetuses were euthanized 7 days later.

RESULTS

Ischemia was associated with loss of total and mature oligodendrocytes, reduced expression of myelin proteins and induction of microglia and astrocytes, compared with sham controls (P < 0.05). Both hypothermia protocols were associated with a significant increase in numbers of total and mature oligodendrocytes, area fraction of myelin proteins and reduced numbers of microglia and astrocytes, compared with ischemia-normothermia (P < 0.05). There was no difference in the number of oligodendrocytes, microglia or astrocytes or expression of myelin proteins between fast and slow rewarming after hypothermia.

CONCLUSION

The rate of rewarming after a clinically relevant duration of hypothermia had no apparent effect on white matter protection by hypothermia after cerebral ischemia in near-term fetal sheep.

IMPACT

Persistent white matter injury is a major contributor to long-term disability after neonatal encephalopathy despite treatment with therapeutic hypothermia. The optimal rate to rewarm infants after therapeutic hypothermia is unclear; current protocols were developed on a precautionary basis. We now show that slow rewarming at 0.5 °C/h did not improve histological white matter injury compared with rapid spontaneous rewarming after a clinically established duration of hypothermia in near-term fetal sheep.

A lipidated peptide derived from the C-terminal tail of the vasopressin 2 receptor shows promise as a new β-arrestin inhibitor

β-arrestins play pivotal roles in seven transmembrane receptor (7TMR) signalling and trafficking. To study their functional role in regulating specific receptor systems, current research relies mainly on genetic tools, as few pharmacological options are available. To address this issue, we designed and synthesised a novel lipidated phosphomimetic peptide inhibitor targeting β-arrestins, called ARIP, which was developed based on the C-terminal tail (A343-S371) of the vasopressin V2 receptor. As the V2R sequence has been shown to bind β-arrestins with high affinity, we added an N-terminal palmitate residue to allow membrane tethering and cell entry. Here, using BRET2-based biosensors, we demonstrated the ability of ARIP to inhibit agonist-induced β-arrestin recruitment on a series of 7TMRs that includes both stable and transient β-arrestin binders, with efficiencies that depend on receptor type. In addition, we showed that ARIP was unable to recruit β-arrestins to the cell membrane by itself, and that it did not interfere with G protein signalling. Molecular modelling studies also revealed that ARIP binds β-arrestins as does V2Rpp, the phosphorylated peptide derived from V2R, and that replacing the p-Ser and p-Thr residues of V2Rpp with Glu residues does not alter ARIP's inhibitory activity on β-arrestin recruitment. Importantly, ARIP exerted an opioid-sparing effect in vivo, as intrathecal injection of ARIP potentiated morphine's analgesic effect in the tail-flick test, consistent with previous findings of genetic inhibition of β-arrestins. ARIP therefore represents a promising pharmacological tool for investigating the fine-tuning roles of β-arrestins in 7TMR-driven pathophysiological processes.

Antenatal betamethasone augments lung perfusion but lowers upper body blood flow and O2 delivery with delayed cord clamping at birth in preterm lambs

Although the corticosteroid betamethasone is routinely administered to accelerate lung and cardiovascular maturation in the preterm fetus prior to birth, and use of delayed cord clamping (DCC) is recommended at birth by professional bodies, it is unknown whether antenatal betamethasone alters perinatal pulmonary or systemic arterial blood flow accompaniments of DCC. To address this issue, preterm fetal lambs [gestation 127 (1) days, term = 147 days] with (n = 10) or without (n = 10) antenatal betamethasone treatment were acutely instrumented under general anaesthesia with flow probes to obtain left (LV) and right ventricular (RV) outputs, major central arterial blood flows and shunt flow across both the ductus arteriosus and foramen ovale (FO). After delivery, lambs underwent initial ventilation for 2 min prior to DCC. During initial ventilation and after DCC, betamethasone (1) augmented rises in pulmonary arterial blood flow, with this greater increase supported during initial ventilation by enhanced pulmonary distribution of a higher RV output that was largely underpinned by newly emergent and substantial left-to-right (L → R) shunting across the FO, and after DCC, by an added contribution from more pronounced L → R ductal shunting; (2) increased a redistribution of LV output away from the upper body region, accompanied by lowering of upper body blood flow and O2 delivery; and (3) accentuated a progressive systemic-to-pulmonary arterial shift in the distribution of the combined LV and RV output that occurred in conjunction with more pronounced perinatal L → R shunting. These findings suggest that antenatal betamethasone substantially alters arterial blood flow effects of initial ventilation and DCC in the preterm birth transition. KEY POINTS: Betamethasone is given to increase fetal lung and cardiovascular maturation prior to preterm birth, while delayed cord clamping (DCC) is recommended at birth. Whether antenatal betamethasone alters perinatal arterial blood flow responses to DCC is unknown. Anaesthetized preterm fetal lambs with or without betamethasone pretreatment were instrumented with central arterial flow probes and, at birth, underwent ∼2 min of ventilation before DCC. Betamethasone augmented perinatal rises in pulmonary arterial blood flow, related to enhanced pulmonary distribution during initial ventilation of a higher right ventricular output largely underpinned by left-to-right (L → R) shunting across the foramen ovale, with an added contribution from more pronounced L → R ductal shunting after DCC. Betamethasone increased a redistribution of left ventricular output away from the upper body region, with lowering of upper body blood flow and O2 delivery. Betamethasone accentuated a systemic-to-pulmonary arterial shift in the distribution of combined ventricular output occurring with greater perinatal L → R shunting.

Endothelial and neuronal engagement by AAV-BR1 gene therapy alleviates neurological symptoms and lipid deposition in a mouse model of Niemann-Pick type C2

BACKGROUND

Patients with the genetic disorder Niemann-Pick type C2 disease (NP-C2) suffer from lysosomal accumulation of cholesterol causing both systemic and severe neurological symptoms. In a murine NP-C2 model, otherwise successful intravenous Niemann-Pick C2 protein (NPC2) replacement therapy fails to alleviate progressive neurodegeneration as infused NPC2 cannot cross the blood-brain barrier (BBB). Genetic modification of brain endothelial cells (BECs) is thought to enable secretion of recombinant proteins thereby overcoming the restrictions of the BBB. We hypothesized that an adeno-associated virus (AAV-BR1) encoding the Npc2 gene could cure neurological symptoms in Npc2-/- mice through transduction of BECs, and possibly neurons via viral passage across the BBB.

METHODS

Six weeks old Npc2-/- mice were intravenously injected with the AAV-BR1-NPC2 vector. Composite phenotype scores and behavioral tests were assessed for the following 6 weeks and visually documented. Post-mortem analyses included gene expression analyses, verification of neurodegeneration in Purkinje cells, determination of NPC2 transduction in the CNS, assessment of gliosis, quantification of gangliosides, and co-detection of cholesterol with NPC2 in degenerating neurons.

RESULTS

Treatment with the AAV-BR1-NPC2 vector improved motor functions, reduced neocortical inflammation, and preserved Purkinje cells in most of the mice, referred to as high responders. The vector exerted tropism for BECs and neurons resulting in a widespread NPC2 distribution in the brain with a concomitant reduction of cholesterol in adjacent neurons, presumably not transduced by the vector. Mass spectrometry imaging revealed distinct lipid alterations in the brains of Npc2-/- mice, with increased GM2 and GM3 ganglioside accumulation in the cerebellum and hippocampus. AAV-BR1-NPC2 treatment partially normalized these ganglioside distributions in high responders, including restoration of lipid profiles towards those of Npc2+/+ controls.

CONCLUSION

The data suggests cross-correcting gene therapy to the brain via delivery of NPC2 from BECs and neurons.

Muscle Cathepsin B treatment improves behavioral and neurogenic deficits in a mouse model of Alzheimer's Disease

Muscle secretes factors during exercise that enhance cognition. Myokine Cathepsin B (Ctsb) is linked to memory function, but its role in neurodegenerative disease is unclear. Here we show that AAV-vector-mediated Ctsb overexpression in skeletal muscle in an Alzheimer's Disease (AD) mouse model (APP/PS1), improves motor coordination, memory function and adult hippocampal neurogenesis, while plaque pathology and neuroinflammation remain unchanged. Additionally, in AD mice, Ctsb treatment modifies hippocampal, muscle and plasma proteomic profiles to resemble that of wildtype controls. Conversely, in wildtype mice, Ctsb expression causes memory deficits and results in protein profiles across tissues that are comparable to AD control mice. In AD mice, Ctsb treatment increases the abundance of hippocampal proteins involved in mRNA metabolism and protein synthesis, including those relevant to adult hippocampal neurogenesis and memory function. Furthermore, Ctsb treatment enhances plasma metabolic and mitochondrial processes, and reduces inflammatory responses. In muscle, Ctsb expression elevates protein translation in AD mice, whereas in wildtype mice mitochondrial proteins decrease. Overall, the biological changes in the treatment groups are consistent with effects on memory function. Thus, skeletal muscle Ctsb application has potential as an AD therapeutic intervention.

Preventing Site-Specific Calpain Proteolysis of Junctophilin-2 Protects Against Stress-Induced Excitation-Contraction Uncoupling and Heart Failure Development

BACKGROUND

Excitation-contraction (E-C) coupling processes become disrupted in heart failure (HF), resulting in abnormal Ca2+ homeostasis, maladaptive structural and transcriptional remodeling, and cardiac dysfunction. Junctophilin-2 (JP2) is an essential component of the E-C coupling apparatus but becomes site-specifically cleaved by calpain, leading to disruption of E-C coupling, plasmalemmal transverse tubule degeneration, abnormal Ca2+ homeostasis, and HF. However, it is not clear whether preventing site-specific calpain cleavage of JP2 is sufficient to protect the heart against stress-induced pathological cardiac remodeling in vivo.

METHODS

Calpain-resistant JP2 knock-in mice (JP2CR) were generated by deleting the primary JP2 calpain cleavage site. Stress-dependent JP2 cleavage was assessed through in vitro cleavage assays and in isolated cardiomyocytes treated with 1 μmol/L isoproterenol by immunofluorescence. Cardiac outcomes were assessed in wild-type and JP2CR mice 5 weeks after transverse aortic constriction compared with sham surgery using echocardiography, histology, and RNA-sequencing methods. E-C coupling efficiency was measured by in situ confocal microscopy. E-C coupling proteins were evaluated by calpain assays and Western blotting. The effectiveness of adeno-associated virus gene therapy with JP2CR, JP2, or green fluorescent protein to slow HF progression was evaluated in mice with established cardiac dysfunction.

RESULTS

JP2 proteolysis by calpain and in response to transverse aortic constriction and isoproterenol was blocked in JP2CR cardiomyocytes. JP2CR hearts are more resistant to pressure-overload stress, having significantly improved Ca2+ homeostasis and transverse tubule organization with significantly attenuated cardiac dysfunction, hypertrophy, lung edema, fibrosis, and gene expression changes relative to wild-type mice. JP2CR preserves the integrity of calpain-sensitive E-C coupling-related proteins, including ryanodine receptor 2, CaV1.2, and sarcoplasmic reticulum calcium ATPase 2a, by attenuating transverse aortic constriction-induced increases in calpain activity. Furthermore, JP2CR gene therapy after the onset of cardiac dysfunction was found to be effective at slowing the progression of HF and superior to wild-type JP2.

CONCLUSIONS

The data presented here demonstrate that preserving JP2-dependent E-C coupling by prohibiting the site-specific calpain cleavage of JP2 offers multifaceted beneficial effects, conferring cardiac protection against stress-induced proteolysis, hypertrophy, and HF. Our data also indicate that specifically targeting the primary calpain cleavage site of JP2 by gene therapy approaches holds great therapeutic potential as a novel precision medicine for treating HF.

IGF-1 LR3 does not promote growth in late-gestation growth-restricted fetal sheep

Insulin-like growth factor-1 (IGF-1) and insulin are important fetal anabolic hormones. Complications of pregnancy, such as placental insufficiency, can lead to fetal growth restriction (FGR) with low-circulating IGF-1 and insulin concentrations and attenuated glucose-stimulated insulin secretion (GSIS), which likely contribute to neonatal glucose dysregulation. We previously demonstrated that a 1-wk infusion of IGF-1 LR3, an IGF-1 analog with low affinity for IGF-binding proteins and high affinity for the IGF-1 receptor, at 6.6 µg·kg-1·h-1 into normal fetal sheep increased body weight but lowered insulin concentrations and GSIS. In this study, FGR fetal sheep received either IGF-1 LR3 treatment at 1.17 ± 0.12 μg·kg-1·h-1 (LR3; n = 7) or vehicle (VEH; n = 7) for 1 wk. Plasma insulin, glucose, oxygen, and amino acids were measured before starting treatment and at the end of the treatment period. GSIS was measured on the final treatment day. Fetal body weights, insulin, glucose, oxygen, and GSIS were not different between groups. Amino acid concentrations decreased in LR3 (baseline vs. final individual means comparison P = 0.0232) but not in VEH (P = 0.3866). In summary, a 1-wk IGF-1 LR3 treatment did not improve growth in FGR fetuses. Insulin concentrations and GSIS were not attenuated by IGF-1 LR3, yet circulating amino acids decreased, which could reflect increased amino acid utilization. We speculate that maintaining amino acid concentrations or raising insulin, glucose, and/or oxygen concentrations to values consistent with normally growing fetuses during IGF-1 LR3 treatment may be necessary to increase fetal growth in the setting of placental insufficiency and FGR.NEW & NOTEWORTHY IGF-1 LR3 treatment administered directly into growth-restricted fetal sheep circulation did not improve fetal growth or attenuate circulating insulin or fetal GSIS. Importantly, IGF-1 LR3 treatment reduced circulating amino acids, notably branched-chain amino acids, which have been shown to potentiate GSIS and protein accretion supporting fetal growth.

Reporting quality of animal research in journals that published the ARRIVE 1.0 or ARRIVE 2.0 guidelines: a cross-sectional analysis of 943 studies

Background

The adherence to the Animals in Research: Reporting In Vivo Experiments (ARRIVE) guidelines across the journals that initially published the guidelines and if adherence has improved since the guidelines update, remains unknown. We aimed to quantify the level of adherence and analyze factors that might influence reporting quality among these journals.

Methods

This cross-sectional study retrospectively analyzed interventional animal experiments published in journals that released ARRIVE 1.0 and 2.0 guidelines in three periods: 5 years before (Pre-ARRIVE 1.0) and after (Post-ARRIVE 1.0) the publication of ARRIVE 1.0, and 1 year after the publication of ARRIVE 2.0 (Post-ARRIVE 2.0). Reviewers independently assessed adherence to the ARRIVE guidelines. Basic information and potential influencing factors were extracted. Adherence data were presented as frequency (percentages). Statistical factors influencing reporting quality were evaluated using the Chi-square test or Fisher's exact test.

Results

215, 330, and 398 experiments were included during Pre-ARRIVE 1.0, Post-ARRIVE 1.0 and Post-ARRIVE 2.0 periods, respectively. None of the included 943 studies reported all 38 subitems, showing only 0%, 0%, and 0.25% studies had an "excellent" reporting quality across the three periods. The overall reporting quality was significantly improved among Pre-ARRIVE 1.0, Post-ARRIVE 1.0 and Post-ARRIVE 2.0 (P<0.001). The rate of studies with "average" reporting quality increased sequentially from 53.95% to 73.94% and then to 90.20%, and those with "poor" reporting quality decreased sequentially from 46.05% to 26.06% and then to 9.55% across the three periods. Specifically, 15 out of 38 (39.5%) subitems and 11 out of 27 (40.7%) similar and comparable subitems demonstrated a significant higher percentage of "fully reported" in Post-ARRIVE 1.0 compared to Pre-ARRIVE 1.0 and in Post-ARRIVE 2.0 compared to Post-ARRIVE 1.0, respectively (P<0.05). Country and journal indexing did not significantly affect reporting quality (both P>0.05). However, significant differences in reporting quality were found among the mandatory adherence to the ARRIVE guidelines in the author's instructions and reference to ARRIVE in the manuscript (both P<0.001).

Conclusions

In the journals that initially published the ARRIVE guidelines, compliance with the guidelines still has room for improvement, though it has increased sequentially since introducing the guidelines. Implementing mandatory adherence requirements in the author's instructions and explicitly recognizing adherence to ARRIVE in articles could enhance the reporting quality of interventional animal experiments.

Protective effect of beta-carotene on hepato-nephrotoxicity of gentamicin in male Wistar rats

BACKGROUND

Despite causing significant tissue damage at the molecular and cellular levels, partly due to its induction of oxidative stress, it remains of interest in medical applications. Beta-carotene, found in fruits and vegetables, is being studied for its antioxidant properties. This study aimed to explore beta-carotene's protective effects against gentamicin-induced hepatorenal toxicity.

METHOD

Thirty male Wistar-rats were divided into five groups. Control group received normal-saline, while the canola group received canola oil (beta-carotene solvent). Gentamicin group received 100 mg/kg gentamicin injections for seven days. Beta-carotene groups were treated with beta-carotene at doses of 10 and 20 mg/kg for 10 days, along with gentamicin from the fourth day for 7 days. Serum and tissue hepatorenal function tests were performed at the end of the study.

RESULTS

Gentamicin resulted in hepatorenal damage. Beta-carotene alongside gentamicin significantly decreased serum SGOT (152.3 ± 12.7 vs. 264.8 ± 9.3 IU/L), SGPT (65.7 ± 2.5 vs. 98.0 ± 4.8 IU/L), creatinine (0.74 ± 0.0 vs. 1.5 ± 0.1 mg/dL), and urea (78.1 ± 10.7 vs. 207.4 ± 23.6 mg/dL) in comparison to gentamicin alone (p < 0.05). Beta-carotene caused a significant decrease in vacuolar degeneration, interstitial nephritis and infiltration of lymphocytes in kidney, and cell necrosis, vacuolar degeneration and infiltration of leukocytes compared to the gentamicin group; additionally, beta-carotene prevented increase in oxidative stress in gentamicin group.

CONCLUSION

Administration of gentamicin alone resulted in hepatorenal toxicity, whereas beta-carotene could prevent gentamicin-induced oxidative stress imbalance and tissue damage. Therefore, beta-carotene could serve as an adjunctive therapy to mitigate hepatorenal toxicity in patients undergoing gentamicin treatment.

Circadian patterns of heart rate variability in fetal sheep after hypoxia-ischaemia: A biomarker of evolving brain injury

Hypoxia-ischaemia (HI) before birth is a key risk factor for stillbirth and severe neurodevelopmental disability in survivors, including cerebral palsy, although there are no reliable biomarkers to detect at risk fetuses that may have suffered a transient period of severe HI. We investigated time and frequency domain measures of fetal heart rate variability (FHRV) for 3 weeks after HI in preterm fetal sheep at 0.7 gestation (equivalent to preterm humans) until 0.8 gestation (equivalent to term humans). We have previously shown that this is associated with delayed development of severe white and grey matter injury, including cystic white matter injury (WMI) resembling that observed in human preterm infants. HI was associated with suppression of time and frequency domain measures of FHRV and reduced their circadian rhythmicity during the first 3 days of recovery. By contrast, circadian rhythms of multiple measures of FHRV were exaggerated over the final 2 weeks of recovery, mediated by a greater reduction in FHRV during the morning nadir, but no change in the evening peak. These data suggest that the time of day at which FHRV measurements are taken affects their diagnostic utility. We further propose that circadian changes in FHRV may be a low-cost, easily applied biomarker of antenatal HI and evolving brain injury. KEY POINTS: Hypoxia-ischaemia (HI) before birth is a key risk factor for stillbirth and probably for disability in survivors, although there are no reliable biomarkers for antenatal brain injury. In preterm fetal sheep, acute HI that is known to lead to delayed development of severe white and grey matter injury over 3 weeks, was associated with early suppression of multiple time and frequency domain measures of fetal heart rate variability (FHRV) and loss of their circadian rhythms during the first 3 days after HI. Over the final 2 weeks of recovery after HI, exaggerated circadian rhythms of frequency domain FHRV measures were observed. The morning nadirs were lower with no change in the evening peak of FHRV. Circadian changes in FHRV may be a low-cost, easily applied biomarker of antenatal HI and evolving brain injury.

Using X-ray velocimetry to measure lung function and assess the efficacy of a pseudomonas aeruginosa bacteriophage therapy for cystic fibrosis

Phase contrast x-ray imaging (PCXI) provides high-contrast images of weakly-attenuating structures like the lungs. PCXI, when paired with 4D X-ray Velocimetry (XV), can measure regional lung function and non-invasively assess the efficacy of emerging therapeutics. Bacteriophage therapy is an emerging antimicrobial treatment option for lung diseases such as cystic fibrosis (CF), particularly with increasing rates of multi-drug-resistant infections. Current efficacy assessment in animal models is highly invasive, typically requiring histological assessment. We aim to use XV techniques as non-invasive alternatives to demonstrate efficacy of bacteriophage therapy for treating Pseudomonas aeruginosa CF lung infections, measuring functional changes post-treatment. Time-resolved in vivo PCXI-CT scans of control, Pseudomonas-infected, and phage-treated mouse lungs were taken at the Australian Synchrotron Imaging and Medical Beamline. Using XV we measured local lung expansion and ventilation throughout the breath cycle, analysing the skew of the lung expansion distribution. CT images allowed visualisation of the projected air volume in the lungs, assessing structural lung damage. XV analysis demonstrated changes in lung expansion between infection and control groups, however there were no statistically significant differences between treated and placebo groups. In some cases where structural changes were not evident in the CT scans, XV successfully detected changes in lung function.

Activation of glial cells induces proinflammatory properties in brain capillary endothelial cells in vitro

Neurodegenerative diseases are often accompanied by neuroinflammation and impairment of the blood-brain barrier (BBB) mediated by activated glial cells through their release of proinflammatory molecules. To study the effects of glial cells on mouse brain endothelial cells (mBECs), we developed an in vitro BBB model with inflammation by preactivating mixed glial cells (MGCs) with lipopolysaccharide (LPS) before co-culturing with mBECs to study the influence of molecules released by activated MGCs. The response of the mBECs to activated MGCs was compared to direct stimulation with LPS. The cytokine profile of activated MGCs was analyzed together with their effects on the mBEC's integrity, expression of tight junction proteins, adhesion molecules, and BBB-specific transport proteins. Stimulation of MGCs significantly upregulated mRNA expression and secretion of several pro-inflammatory cytokines. Co-culturing mBECs with pre-stimulated MGCs significantly affected the barrier integrity of mBECs similar to direct stimulation with LPS. The gene expression levels of tight junction proteins were unaltered, but tight junction proteins revealed rearrangements with respect to subcellular distribution. Compared to direct stimulation with LPS, the expression of cell-adhesion molecules was significantly increased when mBECs were co-cultured with prestimulated MGCs and thus pre-activating MGCs transforms mBECs into a proinflammatory phenotype.

Evaluation of variation in preclinical electroencephalographic (EEG) spectral power across multiple laboratories and experiments: An EQIPD study

The European Quality In Preclinical Data (EQIPD) consortium was born from the fact that publications report challenges with the robustness, rigor, and/or validity of research data, which may impact decisions about whether to proceed with further preclinical testing or to advance to clinical testing, as well as draw conclusions on the predictability of preclinical models. To address this, a consortium including multiple research laboratories from academia and industry participated in a series of electroencephalography (EEG) experiments in mice aimed to detect sources of variance and to gauge how protocol harmonisation and data analytics impact such variance. Ultimately, the goal of this first ever between-laboratory comparison of EEG recordings and analyses was to validate the principles that supposedly increase data quality, robustness, and comparability. Experiments consisted of a Localisation phase, which aimed to identify the factors that influence between-laboratory variability, a Harmonisation phase to evaluate whether harmonisation of standardized protocols and centralised processing and data analysis reduced variance, and a Ring-Testing phase to verify the ability of the harmonised protocol to generate consistent findings. Indeed, between-laboratory variability reduced from Localisation to Harmonisation and this reduction remained during the Ring-Testing phase. Results obtained in this multicentre preclinical qEEG study also confirmed the complex nature of EEG experiments starting from the surgery and data collection through data pre-processing to data analysis that ultimately influenced the results and contributed to variance in findings across laboratories. Overall, harmonisation of protocols and centralized data analysis were crucial in reducing laboratory-to-laboratory variability. To this end, it is recommended that standardized guidelines be updated and followed for collection and analysis of preclinical EEG data.

White matter protection with insulin-like growth factor-1 after hypoxia-ischaemia in preterm foetal sheep

Perinatal hypoxia-ischaemia in extremely preterm infants is associated with long-term neurodevelopmental impairment, for which there is no specific treatment. Insulin-like growth factor-1 can reduce acute brain injury, but its effects on chronic white matter injury after hypoxia-ischaemia are unclear. Preterm-equivalent foetal sheep (0.6 gestation) received either sham-asphyxia or asphyxia induced by umbilical cord occlusion for 30 min, and recovered for either 3 or 35 days after asphyxia. The 35 day recovery groups received either an intracerebroventricular infusion of insulin-like growth factor-1 (1 µg/24 h) or vehicle, from 3 to 14 days after asphyxia. Asphyxia was associated with ventricular enlargement, and loss of frontal and parietal white matter area (P < 0.05 versus sham-asphyxia). This was associated with reduced area fraction of myelin basic protein and numbers of oligodendrocyte transcription factor 2 and mature, anti-adenomatous polyposis coli-positive oligodendrocytes in periventricular white matter (P < 0.05), with persistent inflammation and caspase-3 activation (P < 0.05). Four of eight foetuses developed cystic lesions in temporal white matter. Prolonged infusion with insulin-like growth factor-1 restored frontal white matter area, improved numbers of oligodendrocyte transcription factor 2-positive and mature, anti-adenomatous polyposis coli-positive oligodendrocytes, with reduced astrogliosis and microgliosis after 35 days recovery (P < 0.05 versus asphyxia). One of four foetuses developed temporal cystic lesions. Functionally, insulin-like growth factor-1-treated foetuses had faster recovery of EEG power, but not spectral edge. Encouragingly, these findings show that delayed, prolonged, insulin-like growth factor-1 treatment can improve functional maturation of periventricular white matter after severe asphyxia in the very immature brain, at least in part by suppressing chronic neural inflammation.

Glucocorticoid-Induced Leucine Zipper Protein and Yeast-Extracted Compound Alleviate Colitis and Reduce Fungal Dysbiosis

Inflammatory bowel diseases (IBD) have a complex, poorly understood pathogenesis and lack long-lasting effective treatments. Recent research suggests that intestinal fungal dysbiosis may play a role in IBD development. This study investigates the effects of the glucocorticoid-induced leucine zipper protein (GILZp)", known for its protective role in gut mucosa, and a yeast extract (Py) with prebiotic properties, either alone or combined, in DSS-induced colitis. Both treatments alleviated symptoms via overlapping or distinct mechanisms. In particular, they reduced the transcription levels of pro-inflammatory cytokines IL-1β and TNF-α, as well as the expression of the tight junction protein Claudin-2. Additionally, GILZp increased MUC2 transcription, while Py reduced IL-12p40 and IL-6 levels. Notably, both treatments were effective in restoring the intestinal burden of clinically important Candida and related species. Intestinal mycobiome analysis revealed that they were able to reduce colitis-associated fungal dysbiosis, and this effect was mainly the result of a decreased abundance of the Meyerozima genus, which was dominant in colitic mice. Overall, our results suggest that combined treatment regimens with GILZp and Py could represent a new strategy for the treatment of IBD by targeting multiple mechanisms, including the fungal dysbiosis.

Preclinical study of the antimyotonic efficacy of safinamide in the myotonic mouse model

Mexiletine is the first choice drug in the treatment of non-dystrophic myotonias. However, 30% of patients experience little benefit from mexiletine due to poor tolerability, contraindications and limited efficacy likely based on pharmacogenetic profile. Safinamide inhibits neuronal voltage-gated sodium and calcium channels and shows anticonvulsant activity, in addition to a reversible monoamine oxidase-B inhibition. We evaluated the preclinical effects of safinamide in an animal model of Myotonia Congenita, the ADR (arrested development of righting response) mouse. In vitro studies were performed using the two intracellular microelectrodes technique in current clamp mode. We analyzed sarcolemma excitability in skeletal muscle fibers isolated from male and female ADR (adr/adr) and from Wild-Type (wt/wt) mice, before and after the application of safinamide and the reference compound mexiletine. In ADR mice, the maximum number of action potentials (N-spikes) elicited by a fixed current is higher with respect to that of WT mice. Myotonic muscles show an involuntary firing of action potential called after-discharges. A more potent activity of safinamide compared to mexiletine has been demonstrated in reducing N-spikes and the after-discharges in myotonic muscle fibers. The time of righting reflex (TRR) before and after administration of safinamide and mexiletine was evaluated in vivo in ADR mice. Safinamide was able to reduce the TRR in ADR mice to a greater extent than mexiletine. In conclusion, safinamide counteracted the abnormal muscle hyperexcitability in myotonic mice both in vitro and in vivo suggesting it as an effective drug to be indicated in Myotonia Congenita.

Oleanolic acid alleviating ischemia-reperfusion injury in rat severe steatotic liver via KEAP1/NRF2/ARE

Severe steatosis in donor livers is contraindicated for transplantation due to the high risk of ischemia-reperfusion injury (IRI). Although Ho-1 gene-modified bone marrow mesenchymal stem cells (HO-1/BMMSCs) can mitigate IRI, the role of gut microbiota and metabolites in this protection remains unclear. This study aimed to explore how gut microbiota and metabolites contribute to HO-1/BMMSCs-mediated protection against IRI in severe steatotic livers. Using rat models and cellular models (IAR20 and THLE-2 cells) of steatotic liver IRI, this study revealed that ischemia-reperfusion led to significant liver and intestinal damage, heightened immune responses, impaired liver function, and altered gut microbiota and metabolite profiles in rats with severe steatosis, which were partially reversed by HO-1/BMMSCs transplantation. Integrated microbiome and metabolome analyses identified gut microbial metabolite oleanolic acid as a potential protective agent against IRI. Experimental validation showed that oleanolic acid administration alone alleviated IRI and inhibited ferroptosis in both rat and cellular models. Network pharmacology and molecular docking implicated KEAP1/NRF2 pathway as a potential target of oleanolic acid. Indeed, OA experimentally upregulated NRF2 activity, which underlies its inhibition of ferroptosis and protection against IRI. The gut microbial metabolite OA protects against IRI in severe steatotic liver by promoting NRF2 expression and activity, thereby inhibiting ferroptosis.

Inhibition of reactive oxygen species production accompanying alternatively activated microglia by risperidone in a mouse ketamine model of schizophrenia

Recent studies have highlighted the potential involvement of reactive oxygen species (ROS) and microglia, a major source of ROS, in the pathophysiology of schizophrenia. In our study, we explored how the second-generation antipsychotic risperidone (RIS) affects ROS regulation and microglial activation in the hippocampus using a mouse ketamine (KET) model of schizophrenia. KET administration resulted in schizophrenia-like behaviors in male C57BL/6J mice, such as impaired prepulse inhibition (PPI) of the acoustic startle response and hyper-locomotion. These behaviors were mitigated by RIS. We found that the gene expression level of an enzyme responsible for ROS production (Nox2), which is primarily associated with activated microglia, was lower in KET/RIS-treated mice than in KET-treated mice. Conversely, the levels of antioxidant enzymes (Ho-1 and Gclc) were higher in KET/RIS-treated mice. The microglial density in the hippocampus was increased in KET-treated mice, which was counteracted by RIS. Hierarchical cluster analysis revealed three morphological subtypes of microglia. In control mice, most microglia were resting-ramified (type I, 89.7%). KET administration shifted the microglial composition to moderately ramified (type II, 44.4%) and hyper-ramified (type III, 25.0%). In KET/RIS-treated mice, type II decreased to 32.0%, while type III increased to 34.0%. An in vitro ROS assay showed that KET increased ROS production in dissociated hippocampal microglia, and this effect was mitigated by RIS. Furthermore, we discovered that a NOX2 inhibitor could counteract KET-induced behavioral deficits. These findings suggest that pharmacological inhibition of ROS production by RIS may play a crucial role in ameliorating schizophrenia-related symptoms. Moreover, modulating microglial activation to regulate ROS production has emerged as a novel avenue for developing innovative treatments for schizophrenia.

Discovery of Novel Imidazo[1,2-a]pyridine-Based HDAC6 Inhibitors as an Anticarcinogen with a Cardioprotective Effect

Cardiotoxicity associated with chemotherapy has gradually become the major cause of death in cancer patients. The development of bifunctional drugs with both cardioprotective and antitumor effects has become the future direction. HDAC6 plays important roles in the progression, treatment, and prognosis of cancer and cardiovascular diseases, but bifunctional inhibitors have not been reported. Herein, structure-activity relationship studies driven by pharmacophore-based remodification and fragment-based design were performed to yield highly potent HDAC6 inhibitor I-c4 containing imidazo[1,2-a]pyridine. Importantly, I-c4 effectively suppressed the growth of MGC-803 xenografts in vitro and in vivo by inhibiting the deacetylation pathway without causing myocardial damage after long-term administration. Meanwhile, I-c4 could mitigate severe myocardial damage against H2O2 or myocardial ischemia/reperfusion in vitro and in vivo. Further studies revealed that the cardioprotective effect of I-c4 was associated with reduction of inflammatory cytokines. Taken together, I-c4 may represent a novel lead compound for further development of an anticarcinogen with a cardioprotective effect.

Comparison of the stage-dependent mitochondrial changes in response to pressure overload between the diseased right and left ventricle in the rat

The right ventricle (RV) differs developmentally, anatomically and functionally from the left ventricle (LV). Therefore, characteristics of LV adaptation to chronic pressure overload cannot easily be extrapolated to the RV. Mitochondrial abnormalities are considered a crucial contributor in heart failure (HF), but have never been compared directly between RV and LV tissues and cardiomyocytes. To identify ventricle-specific mitochondrial molecular and functional signatures, we established rat models with two slowly developing disease stages (compensated and decompensated) in response to pulmonary artery banding (PAB) or ascending aortic banding (AOB). Genome-wide transcriptomic and proteomic analyses were used to identify differentially expressed mitochondrial genes and proteins and were accompanied by a detailed characterization of mitochondrial function and morphology. Two clearly distinguishable disease stages, which culminated in a comparable systolic impairment of the respective ventricle, were observed. Mitochondrial respiration was similarly impaired at the decompensated stage, while respiratory chain activity or mitochondrial biogenesis were more severely deteriorated in the failing LV. Bioinformatics analyses of the RNA-seq. and proteomic data sets identified specifically deregulated mitochondrial components and pathways. Although the top regulated mitochondrial genes and proteins differed between the RV and LV, the overall changes in tissue and cardiomyocyte gene expression were highly similar. In conclusion, mitochondrial dysfuntion contributes to disease progression in right and left heart failure. Ventricle-specific differences in mitochondrial gene and protein expression are mostly related to the extent of observed changes, suggesting that despite developmental, anatomical and functional differences mitochondrial adaptations to chronic pressure overload are comparable in both ventricles.

Human HPSE2 gene transfer ameliorates bladder pathophysiology in a mutant mouse model of urofacial syndrome

Rare early-onset lower urinary tract disorders include defects of functional maturation of the bladder. Current treatments do not target the primary pathobiology of these diseases. Some have a monogenic basis, such as urofacial, or Ochoa, syndrome (UFS). Here, the bladder does not empty fully because of incomplete relaxation of its outflow tract, and subsequent urosepsis can cause kidney failure. UFS is associated with biallelic variants of HPSE2, encoding heparanase-2. This protein is detected in pelvic ganglia, autonomic relay stations that innervate the bladder and control voiding. Bladder outflow tracts of Hpse2 mutant mice display impaired neurogenic relaxation. We hypothesized that HPSE2 gene transfer soon after birth would ameliorate this defect and explored an adeno-associated viral (AAV) vector-based approach. AAV9/HPSE2, carrying human HPSE2 driven by CAG, was administered intravenously into neonatal mice. In the third postnatal week, transgene transduction and expression were sought, and ex vivo myography was undertaken to measure bladder function. In mice administered AAV9/HPSE2, the viral genome was detected in pelvic ganglia. Human HPSE2 was expressed and heparanase-2 became detectable in pelvic ganglia of treated mutant mice. On autopsy, wild-type mice had empty bladders, whereas bladders were uniformly distended in mutant mice, a defect ameliorated by AAV9/HPSE2 treatment. Therapeutically, AAV9/HPSE2 significantly ameliorated impaired neurogenic relaxation of Hpse2 mutant bladder outflow tracts. Impaired neurogenic contractility of mutant detrusor smooth muscle was also significantly improved. These results constitute first steps towards curing UFS, a clinically devastating genetic disease featuring a bladder autonomic neuropathy.

Peripheral gating of mechanosensation by glial diazepam binding inhibitor

We report that diazepam binding inhibitor (DBI) is a glial messenger mediating crosstalk between satellite glial cells (SGCs) and sensory neurons in the dorsal root ganglion (DRG). DBI is highly expressed in SGCs of mice, rats, and humans, but not in sensory neurons or most other DRG-resident cells. Knockdown of DBI results in a robust mechanical hypersensitivity without major effects on other sensory modalities. In vivo overexpression of DBI in SGCs reduces sensitivity to mechanical stimulation and alleviates mechanical allodynia in neuropathic and inflammatory pain models. We further show that DBI acts as an unconventional agonist and positive allosteric modulator at the neuronal GABAA receptors, particularly strongly affecting those with a high-affinity benzodiazepine binding site. Such receptors are selectively expressed by a subpopulation of mechanosensitive DRG neurons, and these are also more enwrapped with DBI-expressing glia, as compared with other DRG neurons, suggesting a mechanism for a specific effect of DBI on mechanosensation. These findings identified a communication mechanism between peripheral neurons and SGCs. This communication modulates pain signaling and can be targeted therapeutically.

Chronic consequences of ischemic stroke: Profiling brain injury and inflammation in a mouse model with reperfusion

Stroke is a pervasive and debilitating global health concern, necessitating innovative therapeutic strategies, especially during recovery. While existing literature often focuses on acute interventions, our study addresses the uniqueness of brain tissue during wound healing, emphasizing the chronic phase following the commonly used middle cerebral artery (MCA) occlusion model. Using clinically relevant endpoints in male and female mice such as magnetic resonance imaging (MRI) and plasma neurofilament light (NFL) measurement, along with immunohistochemistry, we describe injury evolution. Our findings document significant alterations in edema, tissue remodeling, and gadolinium leakage through MRI. Plasma NFL concentration remained elevated at 30 days poststroke. Microglia responses are confined to the region adjacent to the injury, rather than continued widespread activation, and boron-dipyrromethene (BODIPY) staining demonstrated the persistent presence of foam cells within the infarct. Additional immunohistochemistry highlighted sustained B and T lymphocyte presence in the poststroke brain. These observations underscore potentially pivotal roles played by chronic inflammation brought on by the lipid-rich brain environment, and chronic blood-brain barrier dysfunction, in the development of secondary neurodegeneration. This study sheds light on the enduring consequences of ischemic stroke in the most used rodent stroke model and provides valuable insights for future research, clinical strategies, and therapeutic development.

Mitochondrial respiration is lower in the intrauterine growth-restricted fetal sheep heart

Fetuses affected by intrauterine growth restriction have an increased risk of developing heart disease and failure in adulthood. Compared with controls, late gestation intrauterine growth-restricted (IUGR) fetal sheep have fewer binucleated cardiomyocytes, reflecting a more immature heart, which may reduce mitochondrial capacity to oxidize substrates. We hypothesized that the late gestation IUGR fetal heart has a lower capacity for mitochondrial oxidative phosphorylation. Left (LV) and right (RV) ventricles from IUGR and control (CON) fetal sheep at 90% gestation were harvested. Mitochondrial respiration (states 1-3, LeakOmy, and maximal respiration) in response to carbohydrates and lipids, citrate synthase (CS) activity, protein expression levels of mitochondrial oxidative phosphorylation complexes (CI-CV), and mRNA expression levels of mitochondrial biosynthesis regulators were measured. The carbohydrate and lipid state 3 respiration rates were lower in IUGR than CON, and CS activity was lower in IUGR LV than CON LV. However, relative CII and CV protein levels were higher in IUGR than CON; CV expression level was higher in IUGR than CON. Genes involved in lipid metabolism had lower expression in IUGR than CON. In addition, the LV and RV demonstrated distinct differences in oxygen flux and gene expression levels, which were independent from CON and IUGR status. Low mitochondrial respiration and CS activity in the IUGR heart compared with CON are consistent with delayed cardiomyocyte maturation, and CII and CV protein expression levels may be upregulated to support ATP production. These insights will provide a better understanding of fetal heart development in an adverse in utero environment. KEY POINTS: Growth-restricted fetuses have a higher risk of developing and dying from cardiovascular diseases in adulthood. Mitochondria are the main supplier of energy for the heart. As the heart matures, the substrate preference of the mitochondria switches from carbohydrates to lipids. We used a sheep model of intrauterine growth restriction to study the capacity of the mitochondria in the heart to produce energy using either carbohydrate or lipid substrates by measuring how much oxygen was consumed. Our data show that the mitochondria respiration levels in the growth-restricted fetal heart were lower than in the normally growing fetuses, and the expression levels of genes involved in lipid metabolism were also lower. Differences between the right and left ventricles that are independent of the fetal growth restriction condition were identified. These results indicate an impaired metabolic maturation of the growth-restricted fetal heart associated with a decreased capacity to oxidize lipids postnatally.

Immediate cardiopulmonary responses to consecutive pulmonary embolism: a randomized, controlled, experimental study

BACKGROUND

Acute pulmonary embolism (PE) induces ventilation-perfusion mismatch and hypoxia and increases pulmonary pressure and right ventricular (RV) afterload, entailing potentially fatal RV failure within a short timeframe. Cardiopulmonary factors may respond differently to increased clot burden. We aimed to elucidate immediate cardiopulmonary responses during successive PE episodes in a porcine model.

METHODS

This was a randomized, controlled, blinded study of repeated measurements. Twelve pigs were randomly assigned to receive sham procedures or consecutive PEs every 15 min until doubling of mean pulmonary pressure. Cardiopulmonary assessments were conducted at 1, 2, 5, and 13 min after each PE using pressure-volume loops, invasive pressures, and arterial and mixed venous blood gas analyses. ANOVA and mixed-model statistical analyses were applied.

RESULTS

Pulmonary pressures increased after the initial PE administration (p < 0.0001), with a higher pulmonary pressure change compared to pressure change observed after the following PEs. Conversely, RV arterial elastance and pulmonary vascular resistance was not increased after the first PE, but after three PEs an increase was observed (p = 0.0103 and p = 0.0015, respectively). RV dilatation occurred following initial PEs, while RV ejection fraction declined after the third PE (p = 0.004). RV coupling exhibited a decreasing trend from the first PE (p = 0.095), despite increased mechanical work (p = 0.003). Ventilatory variables displayed more incremental changes with successive PEs.

CONCLUSION

In an experimental model of consecutive PE, RV afterload elevation and dysfunction manifested after the third PE, in contrast to pulmonary pressure that increased after the first PE. Ventilatory variables exhibited a more direct association with clot burden.

The effects of CO2 levels and body temperature on brain interstitial pH alterations during the induction of hypoxic-ischemic encephalopathy in newborn pigs

Brain interstitial pH (pHbrain) alterations play a crucial role in the development of hypoxic-ischemic (HI) encephalopathy (HIE) caused by asphyxia in neonates. The newborn pig is one of the most suitable large animal models for studying HIE, however, compared to rats, experimental data on pHbrain alterations during HIE induction are limited. The major objective of the present study was thus to compare pHbrain changes during HIE development induced by experimental normocapnic hypoxia (H) or asphyxia (A), elicited with ventilation of a gas mixture containing 6%O2 or 6%O2/20%CO2, respectively for 20 min, under either normothermia (NT) or hypothermia (HT) (38.5 ± 0.5 °C or 33.5 ± 0.5 °C core temperature, respectively) in anesthetized piglets yielding four groups: H-NT, A-NT, H-HT, and A-HT. pHbrain changes during HI stress and the 60 min reoxygenation period were measured using a pH-selective microelectrode inserted into the parietal cortex through an open cranial window. In all groups, the pHbrain response to HI stress was acidosis, at the nadir pHbrain values dropped from the baseline of 7.27 ± 0.02 to H-NT:5.93 ± 0.30, A-NT:5.90 ± 0.52, H-HT:6.81 ± 0.27, and A-HT:6.27 ± 0.24 indicating that (1) H and A elicited similar, severe brain acidosis under NT greatly exceeding pH changes in arterial blood (pHa dropped to 7.24 ± 0.07 and 6.78 ± 0.03 from 7.52 ± 0.06 and 7.50 ± 0.05, respectively), and (2) HT ameliorated more the brain acidosis induced by H than by A. In all four groups, pHbrain was restored to baseline values without an alkalotic overshoot during the observed reoxygenation, Our findings suggest that under NT either H or A - both commonly employed HI stresses to elicit HIE in piglet models - would result in a similar acidotic pHbrain response without an alkalotic component either during the HI stress or the early reoxygenation period.

Differential responses of cerebral and renal oxygenation to altered perfusion conditions during experimental cardiopulmonary bypass in sheep

We tested whether the brain and kidney respond differently to cardiopulmonary bypass (CPB) and to changes in perfusion conditions during CPB. Therefore, in ovine CPB, we assessed regional cerebral oxygen saturation (rSO2 ) by near-infrared spectroscopy and renal cortical and medullary tissue oxygen tension (PO2 ), and, in some protocols, brain tissue PO2 , by phosphorescence lifetime oximetry. During CPB, rSO2 correlated with mixed venous SO2 (r = 0.78) and brain tissue PO2 (r = 0.49) when arterial PO2 was varied. During the first 30 min of CPB, brain tissue PO2 , rSO2 and renal cortical tissue PO2 did not fall, but renal medullary tissue PO2 did. Nevertheless, compared with stable anaesthesia, during stable CPB, rSO2 (66.8 decreasing to 61.3%) and both renal cortical (90.8 decreasing to 43.5 mm Hg) and medullary (44.3 decreasing to 19.2 mm Hg) tissue PO2 were lower. Both rSO2 and renal PO2 increased when pump flow was increased from 60 to 100 mL kg-1  min-1 at a target arterial pressure of 70 mm Hg. They also both increased when pump flow and arterial pressure were increased simultaneously. Neither was significantly altered by partially pulsatile flow. The vasopressor, metaraminol, dose-dependently decreased rSO2 , but increased renal cortical and medullary PO2 . Increasing blood haemoglobin concentration increased rSO2 , but not renal PO2 . We conclude that both the brain and kidney are susceptible to hypoxia during CPB, which can be alleviated by increasing pump flow, even without increasing arterial pressure. However, increasing blood haemoglobin concentration increases brain, but not kidney oxygenation, whereas vasopressor support with metaraminol increases kidney, but not brain oxygenation.

Tagging the tjp1a Gene in Zebrafish with Monomeric Red Fluorescent Protein Using Biotin Homology Arms

Tjp1a and other tight junction and adherens proteins play important roles in cell-cell adhesion, scaffolding, and forming seals between cells in epithelial and endothelial tissues. In this study, we labeled Tjp1a of zebrafish with the monomeric red fluorescent protein (mRFP) using CRISPR/Cas9-mediated targeted integration of biotin-labeled polymerase chain reaction (PCR) generated templates. Labeling Tjp1a with RFP allowed us to follow membrane and junctional dynamics of epithelial and endothelial cells throughout zebrafish embryo development. For targeted integration, we used short 35 bp homology arms on each side of the Cas9 genomic target site at the C-terminal of the coding sequence in tjp1a. Through PCR using 5' biotinylated primers containing the homology arms, we generated a double-stranded template for homology directed repair containing a flexible linker followed by RFP. Cas9 protein was complexed with the tjp1a gRNA before mixing with the repair template and microinjected into one-cell zebrafish embryos. We confirmed and recovered a precise integration allele at the desired site at the tjp1a C-terminus. Examination of fluorescence reveals RFP cell-cell junctional labeling using confocal imaging. We are currently using this stable tjp1a-mRFPis86 line to examine the behavior and interactions between cells during vascular formation in zebrafish.

Nonbinary 2D Distribution Tool Maps Autonomic Nerve Fiber Clustering in Lumbosacral Ventral Roots of Rhesus Macaques

Neuromodulation of the peripheral nervous system (PNS) by electrical stimulation may augment autonomic function after injury or in neurodegenerative disorders. Nerve fiber size, myelination, and distance between individual fibers and the stimulation electrode may influence response thresholds to electrical stimulation. However, information on the spatial distribution of nerve fibers within the PNS is sparse. We developed a new two-dimensional (2D) morphological mapping tool to assess spatial heterogeneity and clustering of nerve fibers. The L6-S3 ventral roots (VRs) in rhesus macaques were used as a model system to map preganglionic parasympathetic, γ-motor, and α-motor fibers. Random and ground truth distributions of nerve fiber centroids were determined for each VR by light microscopy. The proposed tool allows for nonbinary determinations of fiber heterogeneity by defining the minimum distance between nerve fibers for cluster inclusion and comparisons with random fiber distributions for each VR. There was extensive variability in the relative composition of nerve fiber types and degree of 2D fiber heterogeneity between different L6-S3 VR levels within and across different animals. There was a positive correlation between the proportion of autonomic fibers and the degree of nerve fiber clustering. Nerve fiber cluster heterogeneity between VRs may contribute to varied functional outcomes from neuromodulation.

LanGui tea, an herbal medicine formula, protects against binge alcohol-induced acute liver injury by activating AMPK-NLRP3 signaling

BACKGROUND

LanGui tea, a traditional Chinese medicine formulation comprising of Gynostemma pentaphyllum (Thunb.) Makino, Cinnamomum cassia (L.) J. Presl, and Ampelopsis grossedentata (Hand-Mazz) W.T. Wang, has yet to have its potential contributions to alcoholic liver disease (ALD) fully elucidated. Consequently, the objective of this research is to investigate the protective properties of LanGui tea against binge alcohol-induced ALD and the mechanisms underlying its effects.

METHODS

An experimental model of acute alcohol-induced liver disease was performed to assess the protective effects of extract of LanGui tea (ELG) at both 50 and 100 mg.kg-1 dosages on male C57BL/6 mice. Various parameters, including hepatic histological changes, inflammation, lipids content, as well as liver enzymes and interleukin 1β (IL-1β) in the serum were measured. The pharmacological mechanisms of ELG, specifically its effects on adenosine monophosphate-(AMP)-activated protein kinase (AMPK) and NLR family pyrin domain containing 3 (NLRP3) signaling, were investigated through Western blotting, qRT-PCR, ELISA, immunohistochemistry, immunofluorescence analyses, and by blocking the AMPK activity.

RESULTS

ELG demonstrated a mitigating effect on fatty liver, inflammation, and hepatic dysfunction within the mouse model. This effect was achieved by activating AMPK signaling and inhibitingNLRP3 signaling in the liver, causing a reduction in IL-1β generation. In vitro studies further confirmed that ELG inhibited cell damage and IL-1β production in ethanol-induced hepatocytes by enhancing AMPK-NLRP3 signaling. Conversely, the pharmacological inhibition of AMPK activity nearly abrogated such alteration.

CONCLUSIONS

Thus, LanGui tea emerges as a promising herbal therapy for ALD management involving AMPK-NLRP3 signaling.

Injured sensory neurons-derived galectin-3 contributes to neuropathic pain via programming microglia in the spinal dorsal horn

Emerging studies have demonstrated spinal microglia play a critical role in central sensitization and contribute to chronic pain. Although several mediators that contribute to microglia activation have been identified, the mechanism of microglia activation and its functionally diversified mechanisms in pathological pain are still unclear. Here we report that injured sensory neurons-derived Galectin-3 (Gal3) activates and reprograms microglia in the spinal dorsal horn (SDH) and contributes to neuropathic pain. Firstly, Gal3 is predominantly expressed in the isolectin B4 (IB4)-positive non-peptidergic sensory neurons and significantly up-regulated in dorsal root ganglion (DRG) neurons and primary afferent terminals in SDH in the partial sciatic nerve ligation (pSNL)-induced neuropathic pain model. Gal3 knockout (Gal3 KO) mice showed a significant decrease in mechanical allodynia and Gal3 inhibitor TD-139 produced a significant anti-allodynia effect in the pSNL model. Furthermore, pSNL-induced microgliosis was compromised in Gal3 KO mice. Additionally, intrathecal injection of Gal3 produces remarkable mechanical allodynia by direct activation of microglia, which have enhanced inflammatory responses with TNF-α and IL-1β up-regulation. Thirdly, using single-nuclear RNA sequencing (snRNA-seq), we identified that Gal3 targets microglia and induces reprogramming of microglia, which may contribute to neuropathic pain establishment. Finally, Gal3 enhances excitatory synaptic transmission in excitatory neurons in the SDH via microglia activation. Our findings reveal that injured sensory neurons-derived Gal3 programs microglia in the SDH and contribute to neuropathic pain.

Light: An Extrinsic Factor Influencing Animal-based Research

Light is an environmental factor that is extrinsic to animals themselves and that exerts a profound influence on the regulation of circadian, neurohormonal, metabolic, and neurobehavioral systems of all animals, including research animals. These widespread biologic effects of light are mediated by distinct photoreceptors-rods and cones that comprise the conventional visual system and melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) of the nonvisual system that interact with the rods and cones. The rods and cones of the visual system, along with the ipRGCs of the nonvisual system, are species distinct in terms of opsins and opsin concentrations and interact with one another to provide vision and regulate circadian rhythms of neurohormonal and neurobehavioral responses to light. Here, we review a brief history of lighting technologies, the nature of light and circadian rhythms, our present understanding of mammalian photoreception, and current industry practices and standards. We also consider the implications of light for vivarium measurement, production, and technological application and provide simple recommendations on artificial lighting for use by regulatory authorities, lighting manufacturers, designers, engineers, researchers, and research animal care staff that ensure best practices for optimizing animal health and well-being and, ultimately, improving scientific outcomes.

Total liquid ventilation in an ovine model of extreme prematurity: a randomized study

BACKGROUND

This study aimed at comparing cardiorespiratory stability during total liquid ventilation (TLV)-prior to lung aeration-with conventional mechanical ventilation (CMV) in extremely preterm lambs during the first 6 h of life.

METHODS

23 lambs (11 females) were born by c-section at 118-120 days of gestational age (term = 147 days) to receive 6 h of TLV or CMV from birth. Lung samples were collected for RNA and histology analyses.

RESULTS

The lambs under TLV had higher and more stable arterial oxygen saturation (p = 0.001) and cerebral tissue oxygenation (p = 0.02) than the lambs in the CMV group in the first 10 min of transition to extrauterine life. Although histological assessment of the lungs was similar between the groups, a significant upregulation of IL-1a, IL-6 and IL-8 RNA in the lungs was observed after TLV.

CONCLUSIONS

Total liquid ventilation allowed for remarkably stable transition to extrauterine life in an extremely preterm lamb model. Refinement of our TLV prototype and ventilation algorithms is underway to address specific challenges in this population, such as minimizing tracheal deformation during the active expiration.

IMPACT

Total liquid ventilation allows for remarkably stable transition to extrauterine life in an extremely preterm lamb model. Total liquid ventilation is systematically achievable over the first 6 h of life in the extremely premature lamb model. This study provides additional incentive to pursue further investigation of total liquid ventilation as a transition tool for the most extreme preterm neonates.

The SGLT2 inhibitor Empagliflozin promotes post-stroke functional recovery in diabetic mice

Type-2 diabetes (T2D) worsens stroke recovery, amplifying post-stroke disabilities. Currently, there are no therapies targeting this important clinical problem. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are potent anti-diabetic drugs that also efficiently reduce cardiovascular death and heart failure. In addition, SGLT2i facilitate several processes implicated in stroke recovery. However, the potential efficacy of SGLT2i to improve stroke recovery in T2D has not been investigated. Therefore, we determined whether a post-stroke intervention with the SGLT2i Empagliflozin could improve stroke recovery in T2D mice. T2D was induced in C57BL6J mice by 8 months of high-fat diet feeding. Hereafter, animals were subjected to transient middle cerebral artery occlusion and treated with vehicle or the SGLTi Empagliflozin (10 mg/kg/day) starting from 3 days after stroke. A similar study in non diabetic mice was also conducted. Stroke recovery was assessed using the forepaw grip strength test. To identify potential mechanisms involved in the Empagliflozin-mediated effects, several metabolic parameters were assessed. Additionally, neuronal survival, neuroinflammation, neurogenesis and cerebral vascularization were analyzed using immunohistochemistry/quantitative microscopy. Empagliflozin significantly improved stroke recovery in T2D but not in non-diabetic mice. Improvement of functional recovery was associated with lowered glycemia, increased serum levels of fibroblast growth factor-21 (FGF-21), and the normalization of T2D-induced aberration of parenchymal pericyte density. The global T2D-epidemic and the fact that T2D is a major risk factor for stroke are drastically increasing the number of people in need of efficacious therapies to improve stroke recovery. Our data provide a strong incentive for the potential use of SGLT2i for the treatment of post-stroke sequelae in T2D.