PARP1 Inhibition and Effect on Burn Injury-Induced Inflammatory Response and Cardiac Function.

BACKGROUND: Burn injury induces multiple signaling pathways leading to a significant inflammatory storm that adversely affects multiple organs, including the heart. Poly (ADP-ribose) polymerase inhibitor 1 (PARP1) inhibition, with specific agents such as N-(5,6-Dihydro-6-oxo-2-phenanthridinyl)-2-acetamide (PJ34), is effective in reducing oxidative stress and cytokine expression in the heart. We hypothesized that PARP1 inhibition would reduce inflammatory signaling and protect against burn injury-induced cardiac dysfunction. STUDY DESIGN: Male Sprague-Dawley rats (8 weeks old, 300 to 350 g) were randomly assigned to sham injury (Sham), 60% total body surface area burn (24 hours post burn), or 60% total body surface area burn with intraperitoneal administration of PJ34 (20 mg/kg, 24 hours post burn + PJ34) and sacrificed 24 hours after injury. Cardiac function was determined using Vevo 2100 echocardiography. Genetic expression of 84 specific toll-like receptor-mediated signal transduction and innate immunity genes were examined using microarray to evaluate cardiac tissue. Qiagen GeneGlobe Data Analysis Center was used to analyze expression, and genetic clustering was performed using TreeView V2.0.8 software. Real-time quantitative polymerase chain reaction was used to validate identified differentially expressed genes. RESULTS: Burn injury significantly altered multiple genes in the toll-like receptor signaling, interleukin-17 signaling, tumor necrosis factor signaling, and nuclear factor-κB signaling pathways and led to significant cardiac dysfunction. PARP1 inhibition with PJ34 normalized these signaling pathways to sham levels as well as improved cardiac function to sham levels. CONCLUSIONS: PARP1 inhibition normalizes multiple inflammatory pathways that are altered after burn injury and improves cardiac dysfunction. PARP1 pathway inhibition may provide a novel methodology to normalize multiple burn injury-induced inflammatory pathways in the heart.

Regulation of Key Immune-Related Genes in the Heart Following Burn Injury.

Immune cascade is one of major factors leading to cardiac dysfunction after burn injury. TLRs are a class of pattern-recognition receptors (PRRs) that initiate the innate immune response by sensing conserved molecular patterns for early immune recognition of a pathogen. The Rat Toll-Like Receptor (TLR) Signaling Pathway RT² Profiler PCR Array profiles the expression of 84 genes central to TLR-mediated signal transduction and innate immunity, and is a validated tool for identifying differentially expressed genes (DEGs). We employed the PCR array to identify burn-induced cardiac TLR-signaling-related DEGs. A total of 38 up-regulated DEGs and 19 down-regulated DEGs were identified. Network analysis determined that all DEGS had 10 clusters, while up-regulated DEGs had 6 clusters and down-regulated DEGs had 5 clusters. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that DEGs were involved in TLR signaling, the RIG-I-Like receptor signaling pathway, the IL-17 signaling pathway, and the NFkB signaling pathway. Function analysis indicated that DEGs were associated with Toll-like receptor 2 binding, Lipopeptide binding, Toll-like receptor binding, and NAD(P)+ nucleosidase activity. The validation of 18 up-regulated DEGs (≥10-fold change) and 6 down-regulated DEGs (≤5-fold change) demonstrated that the PCR array is a trusted method for identifying DEGs. The analysis of validated DEG-derived protein-protein interaction networks will guide our future investigations. In summary, this study not only identified the TLR-signaling-pathway-related DEGs after burn injury, but also confirmed that the burn-induced cardiac cytokine cascade plays an important role in burn-induced heart dysfunction. The results will provide the novel therapeutic targets to protect the heart after burn injury.

Nuclear Factor Erythroid 2-Related Factor 2 Activation and Burn-Induced Cardiac Dysfunction.

BACKGROUND: Our previous studies have found that burn injury induces cardiac dysfunction through interruption of the antioxidant-response element (ARE) pathway in cardiac mitochondria. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key regulator that activates many antioxidant enzymes. Oltipraz (Olti) is a Nrf2 activator and a well-known inducer of NQO1 along with other enzymes that comprise the Nrf2-associated antioxidants. We propose that Nrf2 activation will induce the ARE pathway, leading to abrogation of burn-induced cardiac dysfunction. STUDY DESIGN: In this study, we investigated the effect of Nrf2-deficiency in mice on burn-induced cardiac dysfunction. Wild-type (WT) and Nrf2-deficient mice received 30% total body surface area burn injury and were treated with or without Olti and then harvested at 3 hours and 24 hours post burn (3 hpb and 24 hpb). RESULTS: As expected, Nrf2-deficient mice exhibited exacerbated cardiac dysfunction after burn injury, as measured by Vevo 2100 echocardiography. Electron microscopy showed that Nrf2 depletion worsened burn injury-induced cardiac mitochondrial damage. In addition, Nrf2 depletion increased cardiac mitochondrial dysfunction and myocardial fibrosis after burn injury. Treatment with Olti ameliorated the heart dysfunction in burned Nrf2-/+ mice, improved cardiac mitochondrial structure and oxidative phosphorylation, as well as decreased cardiac fibrosis. These results suggest that Nrf2 and its downstream targets modulate cardiac function after burn injury. CONCLUSIONS: In summary, Nrf2 depletion worsens cardiac dysfunction after burn injury. Nrf2 activation, with a drug such as Olti, offers a promising therapeutic strategy for abrogating burn-induced cardiac dysfunction.

Effect of Mitochondrial Antioxidant (Mito-TEMPO) on Burn-Induced Cardiac Dysfunction.

BACKGROUND: Imbalance of oxidants/antioxidants results in heart failure, contributing to mortality after burn injury. Cardiac mitochondria are a prime source of reactive oxygen species (ROS), and a mitochondrial-specific antioxidant may improve burn-induced cardiomyopathy. We hypothesize that the mitochondrial-specific antioxidant, Triphenylphosphonium chloride (Mito-TEMPO), could protect cardiac function after burn. STUDY DESIGN: Male rats had a 60% total body surface area (TBSA) scald burn injury and were treated with/without Mito-TEMPO (7 mg/kg-1, intraperitoneal) and harvested at 24 hours post-burn. Echocardiography (ECHO) was used for measurement of heart function. Masson Trichrome and hematoxylin and eosin (H & E) staining were used for cardiac fibrosis and immune response. Qualitative polymerase chain reaction (qPCR) was used for mitochondrial DNA replication and gene expression. RESULTS: Burn-induced cardiac dysfunction, fibrosis, and mitochondrial damage were assessed by measurement of mitochondrial function, DNA replication, and DNA-encoded electron transport chain-related gene expression. Mito-TEMPO partially improved the abnormal parameters. Burn-induced cardiac dysfunction was associated with crosstalk between the NFE2L2-ARE pathway, PDE5A-PKG pathway, PARP1-POLG-mtDNA replication pathway, and mitochondrial SIRT signaling. CONCLUSIONS: Mito-TEMPO reversed burn-induced cardiac dysfunction by rescuing cardiac mitochondrial dysfunction. Mitochondria-targeted antioxidants may be an effective therapy for burn-induced cardiac dysfunction.

Intussusception in a child with COVID-19 in the USA.

COVID-19, caused by the novel coronavirus strain SARS-CoV-2 that emerged in late 2019, has resulted in a global pandemic. COVID-19 was initially believed to occur less frequently in children with relatively mild disease. However, severe disease and varied presentations have been reported in infected children, one of such being intussusception. There have only been three reported cases of intussusception in the pediatric population infected with COVID-19. In this paper, we will discuss the management and treatment of a novel fourth case of COVID-19-associated intussusception. This case is the first reported in the USA and suggests that COVID-19 may be implicated in the development of intussusception. Pediatricians should consider the possibility of intussusception when a child with COVID-19 presents with abdominal pain.

Enhanced effects of novel oridonin analog CYD0682 for hepatic fibrosis.

BACKGROUND: Activated hepatic stellate cells (HSCs) are responsible for excess extracellular matrix (ECM) protein deposition in liver fibrosis. Previously, our group reported that the natural compound oridonin induces apoptosis, inhibits cell proliferation, and downregulates ECM proteins in activated HSC. In this study, the antifibrogenic effects of oridonin derivative CYD0682 on the activated human LX-2 and rat HSC-T6 stellate cell lines were investigated. METHODS: Cell proliferation was measured by alamarBlue assay. Apoptosis was detected by Cell Death ELISA and staining of Yo-Pro-1 and propidium iodide. Cell cycle was determined by flow cytometry. Immunoblot and immunofluorescence staining were performed for cellular protein expression. RESULTS: CYD0682 treatment significantly inhibited LX-2 cell proliferation in a dose- and time-dependent manner with an IC50 value of 0.49 µM for 48 h, ∼10-fold greater potency than oridonin. Similar results were observed in HSC-T6 cells. In contrast, 2.5 µM of CYD0682 treatment had no significant effects on proliferation of the human hepatocyte cell line C3A. CYD0682 treatment induced LX-2 cell apoptosis and S-phase cell cycle arrest and was associated with activation of p53, p21, and cleaved caspase-3. The myofibroblast marker protein α-smooth muscle actin and major ECM proteins type I collagen and fibronectin were markedly suppressed in a time- and dose-dependent fashion by CYD0682. Furthermore, pretreatment with CYD0682 blocked transforming growth factor-ß-induced type I collagen and fibronectin production. CONCLUSIONS: In comparison with oridonin, its novel derivative CYD0682 may act as a more potent antihepatic fibrosis agent.

Enhanced anti-fibrogenic effects of novel oridonin derivative CYD0692 in hepatic stellate cells.

Oridonin, isolated from Rabdosia rubescens, has been proven to possess various anti-neoplastic and anti-inflammatory properties. Previously, we reported the anti-fibrogenic effects of oridonin for liver in vitro. In the present study, we investigated the effects of a newly designed analog CYD0692 in vitro. Cell viability was measured by Alamar Blue assay. Cell apoptosis was assessed by Cell Death ELISA and Yo-Pro-1 staining. Western blots were performed for cellular proteins. Flow cytometry was used to measure cell cycle regulation. CYD0692 significantly inhibited LX-2 cells proliferation in a dose- and time-dependent manner with an IC50 value of ~0.7 µM for 48 h, ~tenfold greater potency than oridonin. Similar results were observed in HSC-T6 cells. In contrast, on the human hepatocyte cell line C3A, only 12 % of the cell growth was inhibited with 5 µM of CYD0692 treatment for 48 h, while 30 % inhibited at 10 µM. After CYD0692 treatment on LX-2 cells, apoptosis and S-phase cell cycle arrest were induced; cleaved-PARP, p21, and p53 were activated while cyclin-B1 levels declined. In addition, α-smooth muscle actin, type I Collagen, and fibronectin (FN) were markedly down regulated. Transforming growth factor ß1 (TGF ß1) has been identified as a dominant stimulator for ECM production in HSC. Our results indicated that pretreatment with CYD0692 blocked TGF ß1-induced FN expression, thereby decreasing the downstream factors of TGF ß1 signaling, such as Phospho-Smad2/3 and phospho-ERK. In comparison with oridonin, its novel derivative CYD0692 has demonstrated to be a more potent and potentially safer anti-fibrogenic agent for the treatment of hepatic fibrosis.

Heart rate variability analysis is more sensitive at identifying neonatal sepsis than conventional vital signs.

BACKGROUND: Sepsis remains the largest preventable source of neonatal mortality in the world. Heart rate variability (HRV) analysis and noninvasive cardiac output have been shown to be useful adjuncts to sepsis detection in many patient groups. METHODS: With Institutional Review Board approval, 4 septic and 6 nonseptic extremely low birth weight patients were enrolled. Data from septic and healthy patients were collected for 5 hours. Electrocardiogram waveform and traditional vital signs were collected and the RR intervals were calculated; then HRV analysis was performed in both the time and frequency domain. RESULTS: HRV measurements in time domain, heart rate, and pulse oximetry (SpO2) were significantly different in septic patients vs nonseptic controls. CONCLUSIONS: These results indicate that nonconventional vital signs such as HRV are more sensitive than traditionally used vital signs, such as cardiac output and mean arterial pressure, in the confirmation of sepsis in extremely low birth weight neonates. HRV may allow for earlier identification of septic physiology.

Oridonin inhibits hepatic stellate cell proliferation and fibrogenesis.

BACKGROUND: Liver fibrosis is a common response to liver injury and, in severe cases, leads to cirrhosis. The hepatic stellate cells (HSCs) become activated after liver injury and play a significant role in fibrogenesis. The activated HSC is characterized by increased proliferation, overexpression of α smooth muscle actin, and excessive production of extracellular matrix (ECM) proteins. Oridonin, a naturally occurring diterpenoid, has been shown to induce apoptosis in liver and gastric cancer cells. However, its effects on the HSC are unknown. METHODS: We tested the effects of oridonin on the activated human and rat HSC lines LX-2 and HSC-T6, and the human hepatocyte cell line C3A. Transforming growth factor ß1 (TGF-ß1) was used to stimulate LX-2 cells. RESULTS: Oridonin significantly inhibited LX-2 and HSC-T6 proliferation. In contrast, oridonin had no antiproliferative effect on C3A cells at our tested range. Oridonin induced apoptosis and S-phase arrest in LX-2 cells. These findings were associated with an increase in p53, p21, p16, and cleaved Poly (ADP-ribose) Polymerase (PARP), and with a decrease in Cyclin-dependent kinase 4 (Cdk4). Oridonin markedly decreased expression of α smooth muscle actin and ECM protein type I collagen and fibronectin, blocked TGF-ß1-induced Smad2/3 phosphorylation and type I collagen expression. CONCLUSIONS: Oridonin induces apoptosis and cell cycle arrest involving the p53-p21 pathway in HSC and appears to be nontoxic to hepatocytes. In addition, oridonin suppressed endogenous and TGF-ß1-induced ECM proteins. Thus, oridonin may act as a novel agent to prevent hepatic fibrosis.

Hypertonic saline alters hydraulic conductivity and up-regulates mucosal/submucosal aquaporin 4 in resuscitation-induced intestinal edema.

OBJECTIVE: To characterize membrane conductivity by applying mathematical modeling techniques and immunohistochemistry and to localize and predict areas of the bowel where aquaporins may be associated with edema resolution/prevention associated with hypertonic saline. Intestinal edema induced by resuscitation and mesenteric venous hypertension impairs intestinal transit/contractility. Hypertonic saline decreases intestinal edema and improves transit. Aquaporins are water transport membrane proteins that may be up-regulated with edema and/or hypertonic saline. DESIGN: Laboratory study. SETTING: University research laboratory. SUBJECTS: Male Sprague Dawley rats, weighing 270 to 330 g. INTERVENTIONS: Rats were randomized to control (with and without hypertonic saline) and mesenteric venous hypertension with either 80 mL/kg normal saline (RESUS + VH + VEH) or 80 mL/kg normal saline with hypertonic saline (RESUS + VH + HTS). After 6 hrs, intestinal wet/dry ratios, urine output, peritoneal fluid, and intraluminal fluid were measured. Hydraulic conductivity was calculated from our previously known and published pressure-flow data. The cDNA microarray, Western blot, polymerase chain reaction, and immunohistochemistry studies were conducted for candidate aquaporins and distribution in intestinal edema resolution. MEASUREMENTS AND MAIN RESULTS: Hypertonic saline decreased edema and increased urine, intraluminal, and peritoneal fluid volume. RESUS + VH favors fluid flux into the interstitium. Hypertonic saline causes increased hydraulic conductivity at the seromuscular and mucosal surfaces at the same time limiting flow into the interstitium. This is associated with increased aquaporin 4 expression in the intestinal mucosa and submucosa. CONCLUSIONS: Hypertonic saline mitigates intestinal edema development and promotes fluid redistribution secondary to increased membrane conductivity at the mucosal and seromuscular surfaces. This is associated with up-regulation of aquaporin 4 gene expression and protein. Aquaporin 4 may be a useful therapeutic target for strategies to enhance edema resolution.

Pretreatment with bone morphogenetic protein-7 (BMP-7) mimics ischemia preconditioning following intestinal ischemia/reperfusion injury in the intestine and liver.

Intestinal ischemia/reperfusion (I/R) injury has been shown to cause intestinal mucosal injury and adversely affect function. Ischemic preconditioning (IPC) has been shown to protect against intestinal I/R injury by reducing polymorphonuclear leukocyte infiltration, intestinal mucosal injury, and liver injury, and preserve intestinal transit. Bone morphogenetic protein 7 (BMP-7) has been shown to protect against I/R injury in the kidney and brain. Recently, microarray analysis has been used to examine the possible IPC candidate pathways. This work revealed that IPC may work through upregulation of BMP-7. The purpose of this study was to examine if pretreatment with BMP-7 would replicate the effects seen with IPC in the intestine and liver after intestinal I/R. Rats were randomized to six groups: sham, I/R (30 min of superior mesenteric artery occlusion and 6 h of R), IPC+R (three cycles of superior mesenteric artery occlusion for 4 min and R for 10 min), IPC+I/R, BMP-7+R (100 microm/kg recombinant human BMP-7), or BMP-7+I/R. A duodenal catheter was placed, and 30 min before sacrifice, fluorescein isothiocyanate-Dextran was injected. At sacrifice, dye concentrations were measured to determine intestinal transit. Ileal mucosal injury was determined by histology and myeloperoxidase activity was used as a marker of polymorphonuclear leukocyte infiltration. Serum levels of aspartate aminotransferase were measured at sacrifice to determine liver injury. Pretreatment with BMP-7 significantly improved intestinal transit and significantly decreased intestinal mucosal injury and serum aspartate aminotransferase levels, comparable to animals undergoing IPC. In conclusion, BMP-7 protected against intestinal I/R-induced intestinal and liver injury. Bone morphogenetic protein 7 may be a more logical surrogate to IPC in the prevention of injury in the setting of intestinal I/R.