Neuronal vulnerability to fetal hypoxia-reoxygenation injury and motor deficit development relies on regional brain tetrahydrobiopterin levels

Nicotinamide adenine dinucleotide treatment confers resistance to neonatal ischemia and hypoxia: effects on neurobehavioral phenotypes

JOURNAL/nrgr/04.03/01300535-202412000-00031/figure1/v/2024-04-08T165401Z/r/image-tiff Neonatal hypoxic-ischemic brain injury is the main cause of hypoxic-ischemic encephalopathy and cerebral palsy. Currently, there are few effective clinical treatments for neonatal hypoxic-ischemic brain injury. Here, we investigated the neuroprotective and molecular mechanisms of exogenous nicotinamide adenine dinucleotide, which can protect against hypoxic injury in adulthood, in a mouse model of neonatal hypoxic-ischemic brain injury. In this study, nicotinamide adenine dinucleotide (5 mg/kg) was intraperitoneally administered 30 minutes before surgery and every 24 hours thereafter. The results showed that nicotinamide adenine dinucleotide treatment improved body weight, brain structure, adenosine triphosphate levels, oxidative damage, neurobehavioral test outcomes, and seizure threshold in experimental mice. Tandem mass tag proteomics revealed that numerous proteins were altered after nicotinamide adenine dinucleotide treatment in hypoxic-ischemic brain injury mice. Parallel reaction monitoring and western blotting confirmed changes in the expression levels of proteins including serine (or cysteine) peptidase inhibitor, clade A, member 3N, fibronectin 1, 5'-nucleotidase, cytosolic IA, microtubule associated protein 2, and complexin 2. Proteomics analyses showed that nicotinamide adenine dinucleotide ameliorated hypoxic-ischemic injury through inflammation-related signaling pathways (e.g., nuclear factor-kappa B, mitogen-activated protein kinase, and phosphatidylinositol 3 kinase/protein kinase B). These findings suggest that nicotinamide adenine dinucleotide treatment can improve neurobehavioral phenotypes in hypoxic-ischemic brain injury mice through inflammation-related pathways.

Toward Lung Ventilation Imaging Using Hyperpolarized Diethyl Ether Gas Contrast Agent

Hyperpolarized 129Xe gas was FDA-approved as an inhalable contrast agent for magnetic resonance imaging of a wide range of pulmonary diseases in December 2022. Despite the remarkable success in clinical research settings, the widespread clinical translation of HP 129Xe gas faces two critical challenges: the high cost of the relatively low-throughput hyperpolarization equipment and the lack of 129Xe imaging capability on clinical MRI scanners, which have narrow-bandwidth electronics designed only for proton (1H) imaging. To solve this translational grand challenge of gaseous hyperpolarized MRI contrast agents, here we demonstrate the utility of batch-mode production of proton-hyperpolarized diethyl ether gas via heterogeneous pairwise addition of parahydrogen to ethyl vinyl ether. An approximately 0.1-liter bolus of hyperpolarized diethyl ether gas was produced in 1 second and injected in excised rabbit lungs. Lung ventilation imaging was performed using sub-second 2D MRI with up to 2×2 mm2 in-plane resolution using a clinical 0.35 T MRI scanner without any modifications. This feasibility demonstration paves the way for the use of inhalable diethyl ether as a gaseous contrast agent for pulmonary MRI applications using any clinical MRI scanner.

Development of A New Scoring System in Higher Animals for Testing Cognitive Function in the Newborn Period: Effect of Prenatal Hypoxia-Ischemia

Introduction Enhanced models for assessing cognitive function in the neonatal period are imperative in higher animals. Postnatal motor deficits, characteristic of cerebral palsy, emerge in newborn kits within our prenatal-rabbit model of hypoxia-ischemia (HI). In humans, prenatal HI leads to intellectual disability and cerebral palsy. In a study examining cognitive function in newborn rabbits, we explored several questions. Is there a distinction between conditioned and unconditioned kits? Can the kits discern the human face or the lab coat? Do motorically-normal kits, born after prenatal HI, exhibit cognitive deficits? Methods The conditioning protocol was randomly assigned to kits from each litter. For conditioning, the same human, wearing a lab coat, fed the rabbit kits for 9 days before the cognitive test. The 6-arm radial maze was chosen for its simplicity and ease of use. Normally appearing kits, born after uterine ischemia at 79% or 92% term in New Zealand White rabbits, were compared to Naïve kits. On postpartum day 22/23 or 29/30, the 6-arm maze helped determine if the kits recognized the original feeder from bystander (Test-1) or the lab coat on bystander (Test-2). The use of masks of feeder/bystander (Test-3) assessed confounding cues. A weighted score was devised to address variability in entry to maze arms, time, and repeated-trial learning. Results In conditioned kits, both Naïve and HI kits exhibited a significant preference for the face of the feeder, but not the lab coat. Cognitive deficits were minimal in normal-appearing HI kits. Conclusion The weighted score system was amenable to statistical manipulation.

The promising role of tumor-associated macrophages in the treatment of cancer

Macrophages are important components of the immune system. Mature macrophages can be recruited to tumor microenvironment that affect tumor cell proliferation, invasion and metastasis, extracellular matrix remodeling, immune suppression, as well as chemotherapy resistance. Classically activated type I macrophages (M1) exhibited marked tumor killing and phagocytosis. Therefore, using macrophages for adoptive cell therapy has attracted attention and become one of the most effective strategies for cancer treatment. Through cytokines and/or chemokines, macrophage can inhibit myeloid cells recruitment, and activate anti-tumor and immune killing functions. Applying macrophages for anti-tumor delivery is one of the most promising approaches for cancer therapy. This review article introduces the role of macrophages in tumor development and drug resistance, and the possible clinical application of targeting macrophages for overcoming drug resistance and enhancing cancer therapeutics, as well as its challenges.

Transplantation of human neural stem cell prevents symptomatic motor behavior disability in a rat model of Parkinson's disease

Parkinson's disease (PD) is a ubiquitous brain cell degeneration disease and presents a significant therapeutic challenge. By injecting 6-hydroxydopamine (6-OHDA) into the left medial forebrain bundle, rats were made to exhibit PD-like symptoms and treated by intranasal administration of a low-dose (2 × 105) or high-dose (1 × 106) human neural stem cells (hNSCs). Apomorphine-induced rotation test, stepping test, and open field test were implemented to evaluate the motor behavior and high-performance liquid chromatography was carried out to detect dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), serotonin, and 5-hydroxyindole-3-acetic acid in the striatum of rats. Animals injected with 6-OHDA showed significant motor function deficits and damaged dopaminergic system compared to the control group, which can be restored by hNSCs treatment. Treatment with hNSCs significantly increased the tyrosine hydroxylase-immunoreactive cell count in the substantia nigra of PD animals. Moreover, the levels of neurotransmitters exhibited a significant decline in the striatum tissue of animals injected with 6-OHDA when compared to that of the control group. However, transplantation of hNSCs significantly elevated the concentration of DA and DOPAC in the injured side of the striatum. Our study offered experimental evidence to support prospects of hNSCs for clinical application as a cell-based therapy for PD.

BH4 supplementation reduces retinal cell death in ischaemic retinopathy

Dysregulation of nitric oxide (NO) production can cause ischaemic retinal injury and result in blindness. How this dysregulation occurs is poorly understood but thought to be due to an impairment in NO synthase function (NOS) and nitro-oxidative stress. Here we investigated the possibility of correcting this defective NOS activity by supplementation with the cofactor tetrahydrobiopterin, BH4. Retinal ischaemia was examined using the oxygen-induced retinopathy model and BH4 deficient Hph-1 mice used to establish the relationship between NOS activity and BH4. Mice were treated with the stable BH4 precursor sepiapterin at the onset of hypoxia and their retinas assessed 48 h later. HPLC analysis confirmed elevated BH4 levels in all sepiapterin supplemented groups and increased NOS activity. Sepiapterin treatment caused a significant decrease in neuronal cell death in the inner nuclear layer that was most notable in WT animals and was associated with significantly diminished superoxide and local peroxynitrite formation. Interestingly, sepiapterin also increased inflammatory cytokine levels but not microglia cell number. BH4 supplementation by sepiapterin improved both redox state and neuronal survival during retinal ischaemia, in spite of a paradoxical increase in inflammatory cytokines. This implicates nitro-oxidative stress in retinal neurones as the cytotoxic element in ischaemia, rather than enhanced pro-inflammatory signalling.

A systematic review of noninflammatory cerebrospinal fluid biomarkers for clinical outcome in neonates with perinatal hypoxic brain injury that could be biologically significant

Neonatal encephalopathy (NE) that purportedly arises from hypoxia-ischemia is labeled hypoxic-ischemic encephalopathy (HIE). Perinatal asphyxia is a clinical syndrome involving acidosis, a low Apgar score and the need for resuscitation in the delivery room; asphyxia alerts one to the possibility of NE. In the present systematic review, we focused on the noninflammatory biomarkers in cerebrospinal fluid (CSF) that are involved in the development of possible brain injury in asphyxia or HIE. A literature search in PubMed and EMBASE for case-control studies was conducted and 17 studies were found suitable by a priori criteria. Statistical analysis used the Mantel-Haenszel model for dichotomous data. The pooled mean difference and 95% confidence intervals (CIs) were determined. We identified the best biomarkers, based on the estimation approach in evaluating the biological significance, out of hundreds in three categories: cell adhesion and proliferation, oxidants and antioxidants, and cell damage. The following subtotal-population comparisons were made: perinatal asphyxia versus no asphyxia, asphyxia with HIE versus asphyxia without HIE, asphyxia with HIE versus no asphyxia, and term versus preterm HIE newborn with asphyxia. Biological significance of the biomarkers was determined by using a modification of the estimation approach, by ranking the biomarkers according to the difference in the bounds of the CIs. The most promising CSF biomarkers for prognostication especially for the severest HIE include creatine kinase, xanthine oxidase, vascular endothelial growth factor, neuron-specific enolase, superoxide dismutase, and malondialdehyde. Future studies are recommended using such a combined test to prognosticate the most severely affected patients.

Targeted Perioperative Nursing Combined with Propofol and Fentanyl for Gynecological Laparoscopic Surgery

Objective

The aim of this study is to investigate the clinical effects of targeted perioperative nursing combined with propofol and fentanyl in gynecological laparoscopic surgery.

Methods

Patients who were admitted to our hospital for gynecological laparoscopic surgeries from October 1, 2019 to November 30, 2021 were included in this retrospective study. Patients in group A received routine propofol and fentanyl. Patients in group B received targeted perioperative nursing on the basis of interventions in group A. The anesthetic effects, clinical indicators, mental health status, and adverse reactions were compared between the two groups.

Results

A total of 84 qualified patients were retrieved. The total effective anesthesia rate, extubation time, operation time, consciousness recovery time, intraoperative blood loss, hospital stay, SAS score, SDS score, health status indicators, and adverse events in group B were all significantly better than those in group A (P < 0.05 for all comparisons).

Conclusion

Combined intervention (propofol + fentanyl + targeted perioperative care) for gynecological laparoscopic surgery patients has a significant anesthesia effect, which can effectively improve the patient's clinical indicators and mental health status and can also reduce the occurrence of adverse events. It has good safety and can be widely used in clinical practice.

Clinical Study on Blood Pressure Variability, Montreal Cognitive Assessment and Arteriosclerosis Index in Patients with Cerebral Small Vessel Disease Treated with Integrated Traditional Chinese and Western Medicine by Invigorating Kidney and Removing Blood Stasis

Objective

To explore the clinical improvement in blood pressure variability, Montreal Cognitive Assessment, and angiosclerosis index in patients with cerebral small vessel disease treated with integrated traditional Chinese and Western medicine.

Methods

A randomized controlled study of patients with cerebral small vessel disease who were treated in our hospital from November 1, 2018, to January 31, 2022. The enrolled patients were randomized into 2 groups according to the random numbers: an observation group treated with integrated traditional Chinese and Western medicine and a control group treated with Western medicine only. Blood pressure variability, Montreal Cognitive Assessment (MoCA), and angiosclerosis index were compared between the two groups.

Results

There were 71 qualified cases in the observation group and 58 qualified cases in the control group. Before treatment, the indicators between the two groups were comparable (P > 0.05). After treatment, the mean values of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly decreased (P < 0.05); the decrease of 24hSBP-coefficient of variation (CV), daytime SBP (dSBP)-CV, 24hSBP-standard deviation (SD), and dSBP-SD in the observation group was significantly better than that in the control group; the MoCA scores of the observation group were significantly higher than those of the control group ((P < 0.05); the ABI and PWV were significantly different between the two groups (P < 0.05); TC, TG, HDL-C, and LDL-C in observation group decreased after treatment, and HDL-C increased significantly (P < 0.05).

Conclusion

Integrative traditional Chinese and Western medicine treatment can further reduce the blood pressure variability, especially systolic blood pressure; improve the MoCA score and cognitive function, increase the ankle-brachial index, reduce pulse wave velocity and the degree of arteriosclerosis; and improve lipid metabolism a comprehensive intervention role.

Early Identification of High-Risk Factors for Upper Gastrointestinal Bleeding

Objective

To identify simple and accurate pre-endoscopy risk factors for early identification of high-risk upper gastrointestinal bleeding.

Methods

Patients who were admitted to Suzhou Hospital of Integrated Traditional Chinese and Western Medicine from January 1, 2016, to December 31, 2019, due to upper gastrointestinal bleeding were retrieved, and the detailed clinical data of the above patients were collected. Patients with a definite diagnosis of bleeding from esophageal/and gastric varices were assigned to the high-risk group. Patients with bleeding not caused by varices were divided into a high-risk and a low-risk group according to the Forrest grading and scoring standard (high-risk group Forrest Ia-IIb, low-risk group Forrest IIc-III). Univariate analysis, t-test, chi-square test, binary logistic regression, ROC curve (Receiver-operating characteristic curve), etc. were employed for analysis in order to identify some simple and accurate risk factors for high-risk upper digestion tract bleeding before endoscopy.

Results

A total of 916 patients were collected. Three risk factors among the screened risk factors (1) hemoglobin ≤ 85 g/L, (2) vomiting red blood, and (3) “red bloody stool” were analyzed by ROC curve analysis. The specificities of each factor were 78.4%, 94.5%, and 96.7%, respectively, and the sensitivities were 71.8%, 55.9%, and 23.1%, respectively. We also derived a risk prediction scoring system for the three factors that meet the high risk such as (1) hemoglobin ≤ 83 g/L, (2)vomiting red blood, and (3) “red bloody stool.” The area under the ROC curve (AUROC), sensitivity, and specificity were 0.877, 0.904, and 0.746.

Conclusion

Hemoglobin ≤ 85 g/L, vomiting red blood, and red bloody stool were included in a simple scoring standard for predicting high-risk UGIB patients before endoscopy. The new risk prediction scoring system requires only three indicators and has the advantages of high accuracy, short time-consuming, and easy application.

Clinical Characteristics and Treatment of Adult Idiopathic Carpal Tunnel Syndrome Accompanied with Trigger Digit

Purpose

To investigate the clinical characteristics and treatment of adult idiopathic carpal tunnel syndrome (CTS) accompanied with trigger digit.

Materials and Methods

A retrospective analysis was performed on a total of 74 patients with adult idiopathic CTS accompanied with trigger digit admitted to and treated at the Hand Surgery Department of Ningbo No. 6 Hospital from January 1, 2017 to December 31, 2019. Data on patients' gender, age, occupation, course of the disease, menstruation, surgeries, examination-related information, complications, treatment methods, and prognoses during follow-up were recorded and subsequently used to analyze the pathogeneses, clinical characteristics, and treatment.

Results

A total of 74 patients (72 females and 2 males) were included. Among female patients, 51 were postmenopausal and 18 were non-postmenopausal. There were 101 fingers with trigger digit, including 14 patients with trigger digit in both hands, and 115 wrists affected by the CTS. The average course of CTS was 34.5 ± 49.3 months, and that of trigger digit was 10.5 ± 22.4 months. Seventy had both trigger digit and CTS in one hand, while among patients with both hands involved, only 4 had trigger digit or CTS in one hand. Eighty-nine fingers underwent A1 pulley release, and 104 hands underwent carpal tunnel surgery, with steroids being injected under the adventitia of the median nerve during the surgery. All patients who underwent surgeries had I/A-healed incisions, and 14 of them had obvious synovial hyperplasia observed in the carpal tunnel and flexor tendon sheath during surgeries. Follow-up visits, which lasted 3 to 35 months, had an average duration of 1.34 years and included 72 patients. In 63 patients (63/72), the syndrome of tenosynovitis and numbness disappeared and normal hand functions were restored; in 6 patients, the numbness in hands greatly improved and normal hand functions were almost completely restored, while no improvement in numbness of hands and limited hand functions were still observed in 3 patients.

Conclusion

CTS accompanied with trigger digit was more common in postmenopausal females, and the course of CTS was longer than that of trigger digit. CTS and trigger digit were more likely to simultaneously occur in the same hand, while some patients might not have obvious synovial hyperplasia in the carpal tunnel. Surgeries were effective in severe cases.

Carbetocin Controls Intraoperative Blood Loss and Thickness of Myometrium in Scar Uterus Cases

Objective

To study the effect of carbetocin on intraoperative blood loss and thickness of myometrium during cesarean section with the scarred uterus at term pregnancy.

Methods

Pregnant women with full-term gestational scar uterus who underwent cesarean section from March 1, 2021, to April 30, 2022, were retrospectively collected and divided into a reference group (using oxytocin) or a study group (using carbetocin). The clinical data of the two groups were retrospectively analyzed, and the operation time, intraoperative blood loss, hospital stay, uterine contraction effect, changes in the myometrium, and complications were compared between the two groups.

Results

A total of 103 pregnant women were retrieved. There were 44 cases in the reference group and 59 cases in the study group. There were significant differences in operation time, intraoperative bleeding, hospital stay, postoperative adverse events, uterine fundus wall thickness, anterior wall thickness, posterior wall thickness, and uterine contraction effect between the two groups (p=0.0001, 0.005, 0.006, 0.001, 0.0004, 0.003, 0.001, and 0.005, respectively). There were no significant differences in estradiol (E2), luteinizing hormone (LH), or follicle-stimulating hormone (FSH) between the two groups before the surgery (p=0.596, 0.840, and 0.940, respectively), but there were significant differences after the surgery (p=0.011, 0.001, and 0.005, respectively).

Conclusion

The use of carbetocin in the cesarean section of a full-term scar uterus is significantly effective in shortening the operation time, reducing the amount of intraoperative blood loss, and promoting the recovery of the uterus.

Efficacy Evaluation of High-Volume Hemofiltration in Patients with Severe Acute Respiratory Distress Syndrome

Objective

To investigate the efficacy of high-volume hemofiltration (HVHF) in the treatment of severe acute respiratory distress syndrome (ARDS) caused by sepsis and its effect on serum levels of miR-126, miR-184, and MAP1-LC3.

Methods

From July 1, 2015 to December 31, 2021, patients with severe ARDS caused by sepsis who were admitted to our hospital were retrospectively analyzed. Patients who received conventional treatment were summarized into the control group, and those who received HVHF were summarized into the study group. The treatment effects of the two groups were compared.

Results

Ninety-five qualified patients were retrieved, with 42 patients in the control group and 53 patients in the study group. After treatment, the levels of IL-6, IL-10, TNF-α, miR-126, miR-184, and MAP1-LC3 were significantly lower in the study group (P < 0.05 for all), whereas PEF, FRC, TEF25%, heart rate, mean arterial pressure, and blood oxygen were significantly higher in the study group (P < 0.05 for all).

Conclusion

HVHF has a good clinical effect on improving patients with severe ARDS caused by sepsis and can improve the pulmonary function of patients.

Effects of Propofol Intravenous Anesthesia on Serum NGF, S100B Protein, and Immune Function in Patients with Bladder Cancer after Resection

Objective

To explore the efficacy of intravenous propofol anesthesia on patients with bladder cancer after resection, as well as its effect on cognitive and immune function.

Methods

Patients with bladder cancer and received resection of bladder cancer at our hospital from May 1, 2019, to November 30, 2021, were retrospectively retrieved and included in this study. The included patients were summarized into group A (isoflurane) and group B (intravenous propofol). The anesthesia intervention effect, serum NGF level, serum S100B protein level, and immune function before surgery, 6 h after surgery, 1 d after surgery, and 3 d after surgery were compared between the two groups.

Results

Eighty-six patients were retrieved. The anesthesia intervention effective rate of patients in group B was significantly higher than that of patients in group A (P < 0.01). The serum NGF and S100B of patients in both groups were significantly lower on postsurgical day 1, but in the trend to returning to those before intervention level on day 3. There were also fluctuations in immune function represented by changes in CD3+, CD4+, CD8+, and CD4+/CD8+ T cells, which showed return of function by postsurgical day 3.

Conclusion

The anesthetic effect of intravenous propofol in patients with bladder cancer resection is significantly more satisfactory than isoflurane, with a transient effect on serum NGF and S100B protein levels and patients' immune function, which suggests that intravenous propofol can be widely used for general anesthesia in clinical practice.

Efficacy of Postoperative Analgesia by Erector Spinal Plane Block after Lumbar Surgery: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background. In recent years, erector spinae plane block (ESPB) has been increasingly used as a new regional block technique for postoperative analgesia; however, little is known on its benefits. Therefore, we performed a systematic review and meta-analysis to investigate the efficacy and safety of ESPB in lumbar spine surgery. Methods. Databases including PubMed, Embase, Cochrane Library, and Web of Science were systematically searched for randomized controlled trials (RCTs) comparing ESPB with no block in lumbar spine surgery until September 30, 2021. The primary outcome was opioid consumption after surgery. The Cochrane Collaboration’s tool for assessing the risk of bias was used to evaluate the quality of included studies. Results. Fifteen RCTs involving 980 patients were included in the study. Opioid consumption 24 hours after surgery was significantly lower in the ESPB group standardized mean difference ( $\text{SMD}=-2.27$ , 95% confidence interval (95% CI) (-3.21, -1.32); $p<0.01$ ). ESPB reduced pain scores at rest and on movement within 48 hours after surgery and the incidence of the postoperative rescue analgesia ( $\text{RR}=0.32$ , 95% CI (0.31, 0.80); $p=0.02$ ), while it significantly prolonged time to first rescue analgesia ( $\text{SMD}=4.87$ , 95% CI (2.84, 6.90); $p<0.01$ ). Moreover, significantly better patient satisfaction was associated with ESPB ( $\text{SMD}=1.89$ , 95% CI (1.03, 2.74); $p<0.01$ ). Conclusion. EPSB provides effective and safe postoperative analgesia after lumbar spine surgery.

Tetrahydrobiopterin in Cell Function and Death Mechanisms

Significance: Tetrahydrobiopterin (BH4) is most well known as a required cofactor for enzymes regulating cellular redox homeostasis, aromatic amino acid metabolism, and neurotransmitter synthesis. Less well known are the effects dependent on the cofactor's availability, factors governing its synthesis and recycling, redox implications of the cofactor itself, and protein-protein interactions that underlie cell death. This review provides an understanding of the recent advances implicating BH4 in the mechanisms of cell death and suggestions of possible therapeutic interventions. Recent Advances: The levels of BH4 often reflect the sum of synthetic and recycling enzyme activities. Enhanced expression of GTP cyclohydrolase, the rate-limiting enzyme in biosynthesis, increases BH4, leading to improved cell function and survival. Pharmacologically increasing BH4 levels has similar beneficial effects, leading to enhanced production of neurotransmitters and nitric oxide or reducing oxidant levels. The GTP cyclohydrolase-BH4 pairing has been implicated in a type of cell death, ferroptosis. At the cellular level, BH4 counteracts anticancer therapies directed to enhance ferroptosis via glutathione peroxidase 4 (GPX4) activity inhibition. Critical Issues: Because of the multitude of intertwined mechanisms, a clear relationship between BH4 and cell death is not well understood yet. The possibility that the cofactor directly influences cell viability has not been excluded in previous studies when modulating BH4-producing enzymes. Future Directions: The importance of cellular BH4 variations and BH4 biosynthetic enzymes to cell function and viability makes it essential to better characterize temporal changes, cofactor activity, and the influence on redox status, which in turn would help develop novel therapies. Antioxid. Redox Signal. 37, 171-183.

Measurement of Tetrahydrobiopterin in Animal Tissue Samples by HPLC with Electrochemical Detection-Protocol Optimization and Pitfalls

Tetrahydrobiopterin (BH4) is an essential cofactor of all nitric oxide synthase isoforms, thus determination of BH4 levels can provide important mechanistic insight into diseases. We established a protocol for high-performance liquid chromatography/electrochemical detection (HPLC/ECD)-based determination of BH4 in tissue samples. We first determined the optimal storage and work-up conditions for authentic BH4 and its oxidation product dihydrobiopterin (BH2) under various conditions (pH, temperature, presence of antioxidants, metal chelators, and storage time). We then applied optimized protocols for detection of BH4 in tissues of septic (induced by lipopolysaccharide [LPS]) rats. BH4 standards in HCl are stabilized by addition of 1,4-dithioerythritol (DTE) and diethylenetriaminepentaacetic acid (DTPA), while HCl was sufficient for BH2 standard stabilization. Overnight storage of BH4 standard solutions at room temperature in HCl without antioxidants caused complete loss of BH4 and the formation of BH2. We further optimized the protocol to separate ascorbate and the BH4 tissue sample and found a significant increase in BH4 in the heart and kidney as well as higher BH4 levels by trend in the brain of septic rats compared to control rats. These findings correspond to reports on augmented nitric oxide and BH4 levels in both animals and patients with septic shock.

Mesenchymal stem cell secretome protects against oxidative stress-induced ocular blast visual pathologies

Visual deficits are a common concern among subjects with head trauma. Stem cell therapies have gained recent attention in treating visual deficits following head trauma. Previously, we have shown that adipose-derived stem cell (ASC) concentrated conditioned medium (ASC-CCM), when delivered via an intravitreal route, yielded a significant improvement in vision accompanied by a decrease in retinal neuroinflammation in a focal cranial blast model that indirectly injures the retina. The purpose of the current study is to extend our previous studies to a direct ocular blast injury model to further establish the preclinical efficacy of ASC-CCM. Adult C57BL/6J mice were subjected to repetitive ocular blast injury (rOBI) of 25 psi to the left eye, followed by intravitreal delivery of ASC-CCM (∼200 ng protein/2 μl) or saline within 2-3 h. Visual function and histological changes were measured 4 weeks after injury and treatment. In vitro, Müller cells were used to evaluate the antioxidant effect of ASC-CCM. Visual acuity, contrast sensitivity, and b-wave amplitudes in rOBI mice receiving saline were significantly decreased compared with age-matched sham blast mice. Immunohistological analyses demonstrated a significant increase in glial fibrillary acidic protein (a retinal injury marker) in Müller cell processes, DNA/RNA damage, and nitrotyrosine (indicative of oxidative stress) in the retina, while qPCR analysis revealed a >2-fold increase in pro-inflammatory cytokines (TNF-α, ICAM1, and Ccl2) in the retina, as well as markers for microglia/macrophage activation (IL-1β and CD86). Remarkably, rOBI mice that received ASC-CCM demonstrated a significant improvement in visual function compared to saline-treated rOBI mice, with visual acuity, contrast sensitivity, and b-wave amplitudes that were not different from those in sham mice. This improvement in visual function also was associated with a significant reduction in retinal GFAP, neuroinflammation markers, and oxidative stress compared to saline-treated rOBI mice. In vitro, Müller cells exposed to oxidative stress via increasing doses of hydrogen peroxide demonstrated decreased viability, increased GFAP mRNA expression, and reduced activity for the antioxidant catalase. On the other hand, oxidatively stressed Müller cells pre-incubated with ASC-CCM showed normalized GFAP, viability, and catalase activity. In conclusion, our study demonstrates that a single intravitreal injection of ASC-CCM in the rOBI can significantly rescue retinal injury and provide significant restoration of visual function. Our in vitro studies suggest that the antioxidant catalase may play a major role in the protective effects of ASC-CCM, uncovering yet another aspect of the multifaceted benefits of ASC secretome therapies in neurotrauma.

Nitric oxide in cellular adaptation and disease

Nitric oxide synthases are the major sources of nitric oxide, a critical signaling molecule involved in a wide range of cellular and physiological processes. These enzymes comprise a family of genes that are highly conserved across all eukaryotes. The three family members found in mammals are important for inter- and intra-cellular signaling in tissues that include the nervous system, the vasculature, the gut, skeletal muscle, and the immune system, among others. We summarize major advances in the understanding of biochemical and tissue-specific roles of nitric oxide synthases, with a focus on how these mechanisms enable tissue adaptation and health or dysfunction and disease. We highlight the unique mechanisms and processes of neuronal nitric oxide synthase, or NOS1. This was the first of these enzymes discovered in mammals, and yet much remains to be understood about this highly conserved and complex gene. We provide examples of two areas that will likely be of increasing importance in nitric oxide biology. These include the mechanisms by which these critical enzymes promote adaptation or disease by 1) coordinating communication by diverse cell types within a tissue and 2) directing cellular differentiation/activation decisions processes.