Evaluating Adverse Reactions of Central Venous Catheter Placement in Patients with AIDS: A Meta-Analysis Approach.

Objective: This study aims to identify contributing factors to adverse reactions related to central venous catheter (CVC) usage in patients with HIV/AIDS, to enhance patient care and treatment outcomes. Methods: To obtain the most relevant and recent findings, we conducted a systematic search across reputable databases, including PubMed, EMBASE, and the Cochrane Library, focusing on randomized controlled trials from 2010 to 2023. Two researchers independently led the literature search and screening process, using a thorough pre-structured form for data extraction and performing a risk of bias assessment on selected studies. Statistical synthesis of the data was conducted using the advanced Review Manager 5.3 software. We compared the prevalence of opportunistic infections, the rate of venous inflammation, and the incidence of venous thrombosis in patients with HIV/AIDS undergoing central venous catheter placement. Results: The comprehensive exploration led to the inclusion of seven randomized controlled trials, involving 251 instances of central venous catheter placements in patients with HIV/AIDS. The meta-analysis findings revealed a lower prevalence of opportunistic infections in patients with CVCs placed, as indicated by the relative risk [95% Confidence Interval (CI) (2.53), P < .01]. Similarly, the rate of venous inflammation was significantly reduced [95% CI (2.53), P < .01]. However, the rates of venous thrombosis showed no statistically significant variance [95% CI (2.01), P > .1]. Conclusions: The use of central venous catheters in treating HIV/AIDS patients appears to reduce the occurrence of opportunistic infections and venous inflammation, suggesting potential therapeutic benefits. However, the presence of biases within the included studies and notable heterogeneity among them impede the reliability of these conclusions. Therefore, it is imperative to pursue validation through additional high-quality clinical trials.

The effectiveness of fracture liaison services in patients with hip fractures: A systematic review and meta-analysis of randomized controlled trials.

Background: In recent years, fracture liaison services (FLS) have been applied for hip fractures; however, their effectiveness remains uncertain. Objective: To evaluate the effectiveness of FLS in patients with hip fractures. Design: A systematic review and meta-analysis of randomized controlled trials. Data sources: Embase, PubMed, Cochrane Library, Ebsco, Ovid, Web of Science, Medline, CNKI, Wangfang, and Vip were searched from their date of inception to March 2023. Two researchers screened the literature based on the inclusion and exclusion criteria, evaluated the quality, extracted data, and conducted a meta-analysis using ReviewManager 5.4. Results: After screening, 12 randomised controlled trials (RCT) including 2136 patients were used in the meta-analysis. The primary outcomes were hip function rate of recurrent fracture, medication adherence, and degree of weakness. FLS improved hip function in patients with hip fractures [MD = 9.37, 95 % CI (7.69, 11.06), P < 0.0001], P < 0.0001], medication adherence [OR = 10.59, 95 % CI (1.64, 68.41), P＜0.0001], degree of weakness [MD = -1.45, 95%CI (-1.68，-1.23), P＜0.0001], and reduced the rate of recurrent fractures [OR = 0.60, 95 % CI (0.44, 0.82). Conclusion: Implementation of the FLS management model was beneficial for patients with hip fractures. It can positively impact the prognosis of patients with hip fractures by improving hip function, reducing the rate of recurrent fractures, and improving medication adherence and degree of weakness.

Protection Effect of Elbow Joint Airbag on Patients with Upper Limb Fractures: A Quasi-Randomized Controlled Trial.

Objective: Wound healing is delayed because of swelling after upper limb fracture, and the traditional rehabilitation device used in physical therapy cannot flexibly adjust the fixation. This study aims to evaluate the effect of the designed elbow joint airbag protection device used in patients with upper arm fractures. Methods: This is a quasi-randomized controlled trial. From November 2022 to March 2023, 70 hospitalized patients with unilateral upper arm fractures were recruited from a general tertiary hospital in eastern China. The patients were divided into an experimental group and a control group according to the random number table at 1:1. Among them, 35 patients who received elbow joint airbag protection for post-traumatic limb swelling were assigned to the experimental group, and the other 35 patients were assigned to the control group. The degree of swelling regression, a score of resting pain, and patient comfort level was compared between the two groups. Results: The waiting time from swelling to allowing for surgery and pain score at rest were significantly lower in the experimental group than in the control group (P < .05 and P < .001 respectively). The comfort score of the experimental group was higher than that of the control group (P < .05), and these differences were statistically significant. Conclusions: The elbow joint airbag protection can significantly reduce the waiting time for surgery, lessen the degree of swelling regression, reduce the pain in patients' hands caused by swelling, and significantly improve the comfort level. Hence, it is worth promoting in the clinical practice of orthopedic nursing.

Lymphoepithelioma-like Carcinoma of the Stomach: A Case Successfully Treated with Chemotherapy.

Lymphoepithelioma-like carcinoma of the stomach is a rare gastric tumour. Pathological features include undifferentiated carcinoma mixed with prominent stromal lymphoid infiltration. The incidence is significantly higher in men. Lesions occur more often in upper gastric locations, with lower numbers of lymph node metastases and better overall survival rates than other gastric carcinomas. Because of its rarity, standardised management is currently unavailable. A case of lymphoepithelioma-like carcinoma of the stomach is presented that was successfully treated with chemotherapy consisting of only two cycles of tegafur, gimeracil, and oteracil plus oxaliplatin. Key Words: Lymphoepithelioma-like carcinoma, Stomach, Chemotherapy.

Altered Gut Microbial Metabolites in Amnestic Mild Cognitive Impairment and Alzheimer's Disease: Signals in Host-Microbe Interplay.

Intimate metabolic host-microbiome crosstalk regulates immune, metabolic, and neuronal response in health and disease, yet remains untapped for biomarkers or intervention for disease. Our recent study identified an altered microbiome in patients with pre-onset amnestic mild cognitive impairment (aMCI) and dementia Alzheimer's disease (AD). Thus, we aimed to characterize the gut microbial metabolites among AD, aMCI, and healthy controls (HC). Here, a cohort of 77 individuals (22 aMCI, 27 AD, and 28 HC) was recruited. With the use of liquid-chromatography/gas chromatography mass spectrometry metabolomics profiling, we identified significant differences between AD and HC for tryptophan metabolites, short-chain fatty acids (SCFAs), and lithocholic acid, the majority of which correlated with altered microbiota and cognitive impairment. Notably, tryptophan disorders presented in aMCI and SCFAs decreased progressively from aMCI to AD. Importantly, indole-3-pyruvic acid, a metabolite from tryptophan, was identified as a signature for discrimination and prediction of AD, and five SCFAs for pre-onset and progression of AD. This study showed fecal-based gut microbial signatures were associated with the presence and progression of AD, providing a potential target for microbiota or dietary intervention in AD prevention and support for the host-microbe crosstalk signals in AD pathophysiology.

PDGF-BB promotes vascular smooth muscle cell migration by enhancing Pim-1 expression via inhibiting miR-214.

BACKGROUND: Several studies have indicated that the platelet-derived growth factor/platelet-derived growth factor receptor (PDGF/PDGFR) pathway is involved in the process of atherosclerosis. However, its underlying mechanism remains to be further elucidated. Serine/threonine-protein kinase pim-1 (Pim-1), a member of serine/threonine-specific kinases, is a pro-oncogene published to be related to cell proliferation, apoptosis, and metastasis of cancer cells. Whether Pim-1 is involved in PDGF/PDGFR pathway-mediated coronary atherosclerotic heart disease remains to be elucidated. METHODS: We established a cell model of PDGF-BB-stimulated smooth muscle cells using A7r5 cells. Transwell assay was used to detect the potential of cell migration and invasion. The targeted regulation of Pim-1 by miR-214 was confirmed by luciferase assay. Rescue experiments were performed to determine the role of the PDGF-BB/miR-214/Pim-1 axis on the cell migration of smooth muscle cells by including PDGF-BB treatment, and the overexpression of miR-214 and Pim-1. Quantitative polymerase chain reaction (qPCR) was used to examine the gene expression and western blot was performed to detect the protein expression. RESULTS: Our data indicated that PDGF-BB could effectively enhance smooth muscle cell migration. We also showed Pim-1 was a target of miR-214 in A7r5 cells. The expression of Pim-1 was shown to be upregulated by PDGF-BB via suppression of the expression of miR-214. Moreover, overexpression miR-214 inhibited PDGF-BB-stimulated Pim-1 expression and smooth muscle cell migration via modulating epithelial-mesenchymal transition (EMT), but no change on cell cycle. However, overexpression of Pim-1 reversed miR-214-blocked cell migration by promoting the activation of the STAT3, AKT, and ERK signaling pathways. CONCLUSIONS: Our data suggested that the PDGF/miR-214/Pim-1 axis could be a potential target for coronary atherosclerotic heart disease.

Association between epidermal growth factor gene +61A/G polymorphism and the risk of hepatocellular carcinoma: a meta-analysis based on 16 studies.

BACKGROUND: The association between epidermal growth factor (EGF) gene +61A/G polymorphism (rs4444903) and hepatocellular carcinoma (HCC) susceptibility has been widely reported, but the results were inconsistent. To clarify the effect of this polymorphism on HCC risk, a meta-analysis was performed. METHODS: The PubMed, Embase, Cochrane Library, Web of Science, Chinese BioMedical Literature (CBM), Wanfang and Chinese National Knowledge Infrastructure (CNKI) databases were systematically searched to identify relevant studies published up to December 2013. Data were extracted independently by two authors. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated to assess the strength of association. RESULTS: A total of 16 studies including 2475 HCC cases and 5381 controls were included in this meta-analysis. Overall, a significantly increased HCC risk was observed under all genetic models (G vs. A: OR = 1.383, P < 0.001, 95% CI: 1.174-1.629; GG vs. GA + AA: OR = 1.484, P < 0.001, 95% CI: 1.198-1.838; GG + GA vs. AA: OR = 1.530, P < 0.001, 95% CI: 1.217-1.924; GG vs. AA: OR = 1.958, P < 0.001, 95% CI: 1.433-2.675; GA vs. AA: OR = 1.215, P = 0.013, 95% CI: 1.041-1.418). In the subgroup analyses by ethnicity, a significant association with HCC risk was found in Asian populations (G vs. A: OR = 1.151, P = 0.001, 95% CI: 1.056-1.255), European populations (G vs. A: OR = 1.594, P = 0.027, 95% CI: 1.053-2.413, and African populations (G vs. A: OR = 3.599, P < 0.001, 95% CI: 2.550-5.080), respectively. CONCLUSIONS: Our study shows that EGF +61A/G polymorphism is significantly associated with the increased HCC risk, especially in Asian populations. Further large-scale and well-designed studies are required to confirm this conclusion.

[Single-segment pedicle screw fixation for the treatment of thoracolumbar fractures through the gap of paravertebral muscles].

OBJECTIVE: To compare the clinical effect of thoracolumbar fractures between single-segment pedicle screw fixation approach for the gap of paravertebral muscles and double-segment pedicle screw fixation approach for the stripping of paravertebral muscles. METHODS: From September 2008 to January 2010, 65 patients with incomplete compressed thoracolumbar fractures or burst thoracolumbar fractures with unilateral endplate injury were randomly divided into two groups. Thirty patients were treated with single-segment pedicle screw fixation through the gap of paravertebral muscles (treatment group). Thirty-five patients were treated with double-segment pedicle screw fixation through the stripping of the paravertebral muscles (control group). All the internal fixations were taken out during 10-12 months after operation. Operative time, perioperative blood loss volume and postoperative drainage volume were compared between two groups. At final follow-up, the change of neurological ASIA grade were recorded; and postoperative 5 days and final follow-up, compared Denis classification of lumbar and back pain between two groups; and analyzed the sagittal index and compressibility of anterior border of vertebral body by X -ray lateral projection. RESULTS: All patients were follow-up from 14 to 22 months with an average of 18.3 months. No postoperative infection, secondary spinal cord injury was found. One case of control group occurred internal fixation breakage at the 11th month after operation and other internal fixation no loosening. There was no significant difference in operative time, the recovery of neurological function between the two groups (P > 0.05). Perioperative blood loss volume and postoperative drainage volume of treatment group was less than that of control group (P < 0.01). And in Denis classification of lumbar and back pain, the treatment group recovered more quickly, and the residual pain of lumbar and back was less than that of control group (P < 0.01). Postoperative posterior salient and compression of anterior border of vertebral body improved in two groups (P < 0.01), there was no significant difference in degree of improvement between two groups (P > 0.05); but both loss existed at final follow-up (P < 0.01), there was no significant difference in loss of posterior salient between two groups (P > 0.05). In the treatment group, the loss of rectify of anterior border of vertebral body existed, but it was less than that of the control group. CONCLUSION: In the premise of strict controlling surgery indications, the treatment of thoracolumbar fractures with single-segment pedicle screw fixation through the gap of paraspinal muscles, can effectively recover the height of vertebral body and rectify posterior salient, and reduce the fixed segment. Compared with the traditional operative method of double-segment pedicle screw fixation through the stripping of paraspinal muscle, it can obviously reduce the operation wound and the bleeding, lessen the pain of lumbar and back. And the recent clinical effect is satisfied.

miRNA-939 regulates human inducible nitric oxide synthase posttranscriptional gene expression in human hepatocytes.

Human inducible nitric oxide synthase (hiNOS) gene expression is regulated by transcriptional and posttranscriptional mechanisms. The purpose of this study was to determine whether specific microRNA (miRNA) directly regulate hiNOS gene expression. Sequence analysis of the 496-bp hiNOS 3'-untranslated region (3'-UTR) revealed five putative miR-939 binding sites. The hiNOS 3'-UTR conferred significant posttranscriptional blockade of luciferase activity in human A549, HCT8, and HeLa cells. The hiNOS 3'-UTR also exerted basal and cytokine-stimulated posttranscriptional repression in an orientation-dependent manner. Functional studies demonstrated that transfection of miR-939 into primary human hepatocytes (HCs) significantly inhibited cytokine-induced NO synthesis in a dose-dependent manner that was abrogated by a specific miR-939 inhibitor. MiR-939 (but not other miRNAs) abolished cytokine-stimulated hiNOS protein in human HC, but had no effect on hiNOS mRNA levels. Site-directed mutagenesis of miR-939 bindings sites at +99 or +112 bp in the hiNOS 3'-UTR increased reporter gene expression. Furthermore, intact miR-939 binding sites at +99 or +112 positions were required for posttranscriptional suppression by miR-939. Cytokine stimulation directly increased miR-939 levels in human HC. Transfection of miR-939 inhibitor (antisense miR-939) enhanced cytokine-induced hiNOS protein and increased NO synthesis in vitro in human HC. Finally, cytokine or LPS injection in vivo in mice increased hepatic miR-939 levels. Taken together, these data identify that miR-939 directly regulates hiNOS gene expression by binding in the 3'-UTR to produce a translational blockade. These findings suggest dual regulation of iNOS gene expression where cytokines induce iNOS transcription and also increase miR-939, leading to translational inhibition in a check-and-balance system.

Interferon-γ induces autophagy with growth inhibition and cell death in human hepatocellular carcinoma (HCC) cells through interferon-regulatory factor-1 (IRF-1).

Interferon-gamma (IFN-γ) is a pleiotropic cytokine with immunomodulatory, anti-viral, and anti-proliferative effects. In this study, we examined the effects of IFN-γ on autophagy and cell growth in human hepatocellular carcinoma (HCC) cells. IFN-γ inhibited cell growth of Huh7 cells with non-apoptotic cell death. IFN-γ induced autophagosome formation and conversion/turnover of microtubule associated protein 1 light chain 3 (LC3) protein. Furthermore, overexpression of IRF-1 also induced autophagy in Huh7 cells. Silencing IRF-1 expression with target small hairpin RNA blocked autophagy induced by IFN-γ. Silencing of the autophagy signals Beclin-1 or Atg5 attenuated the inhibitory effect of IFN-γ on Huh7 cells with decreased cell death. Additionally, IFN-γ activated autophagy in freshly cultured human HCC cells. Together, these findings show that IFN-γ induces autophagy through IRF-1 signaling pathway and the induction of autophagy contributes to the growth-inhibitory effect of IFN-γ with cell death in human liver cancer cells.

Hepatic B7 homolog 1 expression is essential for controlling cold ischemia/reperfusion injury after mouse liver transplantation.

UNLABELLED: Ischemia/reperfusion (I/R) injury remains a key risk factor significantly affecting morbidity and mortality after liver transplantation (LT). B7 homolog 1 (B7-H1), a recently identified member of the B7 family, is known to play important roles in regulating local immune responses. We hypothesized that B7-H1 plays crucial roles during innate immune responses induced by hepatic I/R injury, and using B7-H1 knockout (KO) liver grafts, we tested this hypothesis in the mouse LT model with 24 hours of cold storage. Cold I/R injury in wild type (WT)-to-WT LT enhanced constitutive B7-H1 expression on dendritic cells and sinusoidal endothelial cells and promptly induced B7-H1 on hepatocytes. When B7-H1 KO liver grafts were transplanted into WT recipients, serum alanine aminotransferase (ALT) and graft necrosis levels were significantly higher than those after WT-to-WT LT. Augmented tissue injury in B7-H1 KO grafts was associated with increased frequencies and absolute numbers of graft CD3(+) T cells (particularly CD8(+) T cells). B7-H1 KO grafts had significantly fewer annexin V(+) CD8(+) T cells, and this indicated a failure to delete infiltrating CD8(+) T cells. To evaluate the relative contributions of parenchymal cell and bone marrow-derived cell (BMDC) B7-H1 expression, we generated and transplanted into WT recipients chimeric liver grafts lacking B7-H1 on parenchymal cells or BMDCs. A selective B7-H1 deficiency on parenchymal cells or BMDCs resulted in similar levels of ALT and liver injury, and this suggested that parenchymal cell and BMDC B7-H1 expression was involved in liver damage control. Human livers up-regulated B7-H1 expression after LT. CONCLUSION: The study demonstrates that graft tissue expression of B7-H1 plays a critical role in regulating inflammatory responses during LT-induced hepatic I/R injury, and negative coregulatory signals may have an important function in hepatic innate immune responses.

A far-upstream Oct-1 motif regulates cytokine-induced transcription of the human inducible nitric oxide synthase gene.

Transcriptional regulation of the human inducible nitric oxide synthase (hiNOS) gene is highly complex and requires an orchestrated flow of positive and negative transcription factors that bind to specific cis-acting upstream response elements. Very little specific information exists about the far-upstream region of the hiNOS gene. Oct-1 protein belongs to the Pit-Oct-Unc domain transcription factor family and is constitutively expressed in all dividing cells. It is essential for proliferation, differentiation, and other key cell processes. However, the role of Oct-1 in regulating hiNOS gene expression has not been reported. In this work, the octamer sequence 5'-ATGCAAAT-3' at -10.2 kb in the hiNOS promoter was identified as high-affinity Oct-1 binding by electrophoretic mobility shift assay in vitro and chromatin immunoprecipitation assay in vivo. Mutation of Oct-1 motif at -10.2 kb in the hiNOS promoter decreased cytokine-induced hiNOS promoter activity by 40%. Cytokine-induced hiNOS promoter activity was also significantly reduced by Oct-1 small interfering RNA targeting. Overexpression of Oct-1 increased cytokine-induced hiNOS protein expression in primary human hepatocytes. Furthermore, the Oct-1 motif at -10.2 kb of the hiNOS promoter conferred increased transcriptional activity to the heterologous thymidine kinase promoter irrespective of cytokine induction. Taken together, this work identifies a far-upstream functional Oct-1 enhancer motif at -10.2 kb in the hiNOS promoter that regulates cytokine-induced hiNOS gene transcription and further underscores tight control mechanisms regulating the expression of the hiNOS gene.

Wnt/beta-catenin signaling regulates cytokine-induced human inducible nitric oxide synthase expression by inhibiting nuclear factor-kappaB activation in cancer cells.

The human inducible nitric oxide synthase (hiNOS) gene is regulated by nuclear factor kappaB (NF-kappaB) and has recently been shown to be a target of the Wnt/beta-catenin pathway. In this study, we tested the hypothesis that Wnt/beta-catenin signaling might regulate cytokine- or tumor necrosis factor alpha (TNFalpha)-induced hiNOS expression through interaction with NF-kappaB. A cytokine mixture of TNFalpha + interleukin (IL)-1beta + IFNgamma induced a 2- to 3-fold increase in hiNOS promoter activity in HCT116 and DLD1 colon cells, but produced a 2-fold decrease in SW480 colon cancer cells. A similar differential activity was seen in liver cancer cells (HepG2, Huh7, and Hep3B). Overexpression of beta-catenin produced a dose-dependent decrease in NF-kappaB reporter activity and decreased cytokine mixture-induced hiNOS promoter activity. Gel shift for TNFalpha-induced hiNOS NF-kappaB activation showed decreased p50 binding and decreased NF-kappaB reporter activity in the beta-catenin-mutant HAbeta18 cells. Conversely, enhanced p50 binding and increased NF-kappaB reporter activity were seen in HAbeta85 cells, which lack beta-catenin signaling. Coimmunoprecipitation confirmed that beta-catenin complexed with both p65 and p50 NF-kappaB proteins. NF-kappaB-dependent Traf1 protein expression also inversely correlated with the level of beta-catenin. Furthermore, SW480 cells stably transformed with wild-type adenomatous polyposis coli showed decreased beta-catenin protein and increased TNFalpha-induced p65 NF-kappaB binding as well as iNOS and Traf1 expression. Finally, beta-catenin inversely correlated with iNOS and Fas expression in vivo in hepatocellular carcinoma tumor samples. Our in vitro and in vivo data show that beta-catenin signaling inversely correlates with cytokine-induced hiNOS and other NF-kappaB-dependent gene expression. These findings underscore the complex role of Wnt/beta-catenin, NF-kappaB, and iNOS signaling in the pathophysiology of inflammation-associated carcinogenesis.

Transcriptional suppression of cytokine-induced iNOS gene expression by IL-13 through IRF-1/ISRE signaling.

IL-13 has been reported as one of the major down-regulators of iNOS expression in various tissues and cells. The molecular mechanism of iNOS suppression by IL-13 remains unclear, especially at the transcriptional stage. In this study, we found that IL-13 inhibited the expression of iNOS mRNA, protein, and NO product in a concentration-dependent manner for cytokine-stimulated rat hepatocytes. The most effective dose for IL-13 inhibitory effect is approximately 5 ng/ml. IL-13 also decreased the rat iNOS transcriptional activity by promoter analysis, but had no effect on iNOS mRNA stability. By using TranSignal Protein/DNA Combo Array, we identified cytokine-stimulated IRF-1/ISRE binding that was decreased by the addition of IL-13. Gel shift assay confirmed that IL-13 reduced the IRF-1/ISRE binding at nucleotides -913 to -923 of the rat iNOS promoter. Western blot revealed that IL-13 diminished the relative amount of IRF-1 protein translocated to the nucleus. Our data demonstrate that IL-13 down-regulates the cytokine-induced iNOS transcription by decreasing iNOS specific IRF-1/ISRE binding activity.

Delayed increase of tyrosine hydroxylase expression in rat nigrostriatal system after traumatic brain injury.

Tyrosine hydroxylase (TH) is the key enzyme for synthesizing dopamine (DA) in dopaminergic neurons and its terminals. Emerging experimental and clinical evidence support the hypothesis of a disturbance in dopamine neurotransmission following traumatic brain injury (TBI). However, the effect of controlled cortical impact (CCI) injury on TH in the nigrostriatal system is currently unknown. To determine if there is an alteration in TH after CCI injury, we examined TH levels at 1 day, 7 days, and 28 days post-injury by utilizing a commercially available antibody specific to TH. Rats were anesthetized and surgically prepared for CCI injury (4 m/s, 3.2 mm) or sham surgery. Injured (N=6) and sham animals (N=6) were sacrificed and coronally sectioned (35 microm thick) through the striatum and substantia nigra (SN) for immunohistochemistry. Additionally, semiquantitative measurements of TH protein in striatal and SN homogenates from injured (N=6) and sham (N=6) rats sacrificed at the appropriate time post-surgery were assessed using Western blot analysis. TH protein is bilaterally increased at 28 days post-injury in nigrostriatal system revealed by immunohistochemistry in injured rats compared to sham controls. Western blot analysis confirms the findings of immunohistochemistry in both striatum and SN. We speculate that the increase in TH in the nigrostriatal system may reflect a compensatory response of dopaminergic neurons to upregulate their synthesizing capacity and a delayed increase in the efficiency of DA neurotransmission after TBI.

Liver I/R injury is improved by the arginase inhibitor, N(omega)-hydroxy-nor-L-arginine (nor-NOHA).

Liver ischemia-reperfusion (I/R) injury is associated with profound arginine depletion due to arginase release from injured hepatocytes. The purpose of this study was to determine whether arginase inhibition with N(omega)-hydroxy-nor-l-arginine (nor-NOHA) would increase circulating arginine levels and decrease hepatic damage during liver I/R injury. The effects of nor-NOHA were initially tested in normal animals to determine in vivo toxicity. In the second series of experiments, orthotopic syngeneic liver transplantation (OLT) was performed after 18 h of cold ischemia time in Lewis rats. Animals were given nor-NOHA (100 mg/kg) or saline before and after graft reperfusion. In normal animals treated with nor-NOHA, there were no histopathological changes to organs, liver enzymes, serum creatinine, or body weight. In the OLT model, animals treated with saline exhibited markedly elevated serum transaminases and circulating arginase protein levels. Nor-NOHA administration blunted the increase in serum arginase activity by 80% and preserved serum arginine levels at 3 h after OLT. Nor-NOHA treatment reduced post-OLT serum liver enzyme release by 50%. Liver histology (degree of necrosis) in nor-NOHA-treated animals was markedly improved compared with the saline-treated group. Furthermore, use of the arginase inhibitor nor-NOHA did not influence polyamine synthesis owing to the decrease in ornithine levels. Arginase blockade represents a potentially novel strategy to combat hepatic I/R injury associated with liver transplantation.

Glycochenodeoxycholate (GCDC) inhibits cytokine induced iNOS expression in rat hepatocytes.

BACKGROUND: Although the accumulation of hydrophobic bile acid (e.g., glycine conjugated chenodeoxycholic acid, GCDC) is considered to be an important factor contributing to cholestatic liver dysfunction, its pathogenesis is poorly understood. The purpose of this study was to examine the effect of the bile salt GCDC on the regulation of iNOS expression, a key immune modulator during liver inflammation. MATERIALS AND METHODS: GCDC significantly decreased cytokine-stimulated iNOS promoter activity, and both iNOS mRNA and protein expression. GCDC decreased iNOS promoter activity by preventing IkappaB degradation and inhibiting NF-kappaB DNA-binding activity. To explore the role of iNOS in bile salt induced apoptosis, we also examined the effect of NO on caspase-3 activity. RESULTS: GCDC strongly induced caspase-3 activity, and this increase was abrogated by both exogenous NO exposure and endogenous NO synthesis. Furthermore, adenoviral iNOS (AdiNOS) pre-treatment decreased acute cholestatic-induced liver injury in a rat bile duct ligation model. CONCLUSIONS: These findings indicate a novel signaling pathway where potentially toxic bile salts down-regulate hepatic iNOS expression. This blockade of the iNOS mediated antiapoptotic phenotype may have important implications in certain liver disorders.

Identification of a classic cytokine-induced enhancer upstream in the human iNOS promoter.

The human inducible NOS (iNOS) promoter transcriptionally regulated by 5' flanking region extending 16 kb upstream that contains cytokine-responsive DNA motifs. In this study, we further identified a classic inducible enhancer located between -5 and -6 kb in the hiNOS upstream promoter. This 1 kb promoter sequence functions as a cytokine-inducible enhancer in an orientation- and position-independent manner in human lung A549 and liver AKN1 cells. This DNA enhancer also confers cytokine inducibility to the heterologous thymidine kinase (TK) promoter. Chromatin immunoprecipitation (ChIP) analysis was applied, and confirmed cytokine-inducible in vivo DNA-protein interactions within this enhancer region. In vivo functional binding of both NF-kappaB (p65/p50) and Stat-1alpha at the -5.8 kb human iNOS promoter site was significantly increased in A549 cells after cytokine stimulation, while only Stat-1alpha bound at the -5.2 kb site. These results identify the -5 to -6 kb promoter region as a classic transcriptional enhancer for the human iNOS gene and provide definitive in vivo evidence of specific NF-kappaB and Stat-1 nuclear protein binding that mediates transcription of the hiNOS gene under cytokine stimulation.

Regulation of human nitric oxide synthase 2 expression by Wnt beta-catenin signaling.

Nitric oxide (NO.), an important mediator of inflammation, and beta-catenin, a component of the Wnt-adenomatous polyposis coli signaling pathway, contribute to the development of cancer. We have identified two T-cell factor 4 (Tcf-4)-binding elements (TBE1 and TBE2) in the promoter of human inducible NO synthase 2 (NOS2). We tested the hypothesis that beta-catenin regulates human NOS2 gene. Mutation in either of the two TBE sites decreased the basal and cytokine-induced NOS2 promoter activity in different cell lines. The promoter activity was significantly reduced when both TBE1 and TBE2 sites were mutated (P < 0.01). Nuclear extract from HCT116, HepG2, or DLD1 cells bound to NOS2 TBE1 or TBE2 oligonucleotides in electrophoretic mobility shift assays and the specific protein-DNA complexes were supershifted with anti-beta-catenin or anti-Tcf-4 antibody. Overexpression of beta-catenin and Tcf-4 significantly increased both basal and cytokine-induced NOS2 promoter activity (P < 0.01), and the induction was dependent on intact TBE sites. Overexpression of beta-catenin or Tcf-4 increased NOS2 mRNA and protein expression in HCT116 cells. Lithium chloride (LiCl), an inhibitor of glycogen synthase kinase-3beta, increased cytosolic and nuclear beta-catenin level, NOS2 expression, and NO. production in primary human and rat hepatocytes and cancer cell lines. Treatment with Wnt-3A-conditioned medium increased beta-catenin and NOS2 expression in fetal human hepatocytes. When administered in vivo, LiCl increased hepatic beta-catenin level in a dose-dependent manner with simultaneous increase in NOS2 expression. These data are consistent with the hypothesis that beta-catenin up-regulates NOS2 and suggest a novel mechanism by which the Wnt/beta-catenin signaling pathway may contribute to cancer by increasing NO. production.