Neuro-inflammatory effects of photodegradative products of bilirubin.

Phototherapy was introduced in the early 1950's, and is the primary treatment of severe neonatal jaundice or Crigler-Najjar syndrome. Nevertheless, the potential biological effects of the products generated from the photodegradation of bilirubin during phototherapy remain unknown. This is very relevant in light of recent clinical observations demonstrating that the use of aggressive phototherapy can increase morbidity or even mortality, in extremely low birthweight (ELBW) infants. The aim of our study was to investigate the effects of bilirubin, lumirubin (LR, its major photo-oxidative product), and BOX A and B (its monopyrrolic oxidative products) on the central nervous system (CNS) using in vitro and ex vivo experimental models. The effects of bilirubin photoproducts on cell viability and expression of selected genes were tested in human fibroblasts, three human CNS cell lines (neuroblastoma SH-SY5Y, microglial HMC3, and glioblastoma U-87 cell lines), and organotypic rat hippocampal slices. Neither bilirubin nor its photo-oxidative products affected cell viability in any of our models. In contrast, LR in biologically-relevant concentrations (25 µM) significantly increased gene expression of several pro-inflammatory genes as well as production of TNF-α in organotypic rat hippocampal slices. These findings might underlie the adverse outcomes observed in ELBW infants undergoing aggressive phototherapy.

Haemorrhage following transoral robotic surgery.

BACKGROUND: To report our experience of postoperative haemorrhage in patients following transoral robotic surgery (TORS). METHODS: Data were collected on patients having TORS. Postoperative haemorrhage within 30 days was graded using the Mayo Clinic grading system. RESULTS: Transoral robotic surgery operations were performed on 122 patients. There were 23 bleeding events classified as minor to severe following 19 operations (16%). Haemorrhage requiring a return to the operating room occurred after 7 operations (6%). The odds of an emergent haemorrhage were 5.19 times greater in patients who had a staged neck dissection after TORS (P = .05). The odds of a postoperative bleeding event were 2.6 times greater in patients receiving a larger resection (P = .107). There were no haemorrhage events in the 36 patients who received a synchronous neck dissection with transcervical ligation of the external carotid artery. CONCLUSIONS: Surgical intervention for TORS haemorrhage occurred in 6% patients. No haemorrhage occurred in patients who had ligation of the external carotid artery.

Management of the lateral neck in well differentiated thyroid cancer.

Lateral neck lymph node metastases in well differentiated thyroid cancer are common, ranging from 30% to 60%, with the majority of these foci identifiable only as microscopic deposits. A skilled ultrasound evaluation of the lymph nodes in the lateral neck is recommended for all patients presenting with newly diagnosed thyroid cancer undergoing surgical management. Ultrasound guided fine needle aspiration biopsy may be used to cytologically confirm suspected lateral neck nodal metastases prior to surgery. For patients with large volume nodal disease, extranodal extension, or multiple nodal metastases, computed tomography (CT) scan of the neck with contrast is an important additional imaging modality to accurately localize disease prior to surgery. Primary surgical management for lateral neck disease typically includes lateral neck dissection in conjunction with total thyroidectomy. Postoperative adjuvant radioactive iodine is typically recommended for patients with clinically evident nodal metastases, or for those with over 5 micrometastatic nodes. In the recurrent or persisting disease setting, complete surgical resection of local and regional disease remains the main treatment approach. However, sub-centimeter nodal disease may take an indolent course, and active surveillance may be a reasonable approach in selected clinical circumstances. Conversely, external beam radiation therapy (EBRT) may be considered for scenarios with unresectable disease, or microscopic residual disease following surgery in a clinically unfavorable setting. Two multi-kinase inhibitors (sorafenib and lenvatinib) are now FDA approved for treatment of RAI refractory thyroid cancer and now play an important role in the management of progressive, metastatic and surgically incurable disease.

Significant burden of nonalcoholic fatty liver disease with advanced fibrosis in the US: a cross-sectional analysis of 2011-2014 National Health and Nutrition Examination Survey.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease in the US. Understanding the epidemiology of NAFLD, with specific focus on individuals with hepatic fibrosis is important to guide healthcare resource planning. AIM: To evaluate prevalence and predictors of hepatic fibrosis among US adults with NAFLD. METHODS: We performed a cross-sectional study using data from the updated 2011-2014 National Health and Nutrition Examination Survey, a national, stratified, multistage sampling survey of non-institutionalised US adults age ≥ 20. METAVIR F2 or greater fibrosis among individuals with NAFLD was assessed using AST to Platelet Ratio Index (APRI) score > 0.7. METAVIR F3 or greater fibrosis was assessed using NAFLD fibrosis score (NFS) > 0.676 and FIB-4 score > 3.25. Multivariate logistic regression models evaluated for predictors of fibrosis among individuals with NAFLD. RESULTS: Overall prevalence of NAFLD among US adults was 21.9% (95% CI 20.6-23.3), representing 51.6 million adults. Among individuals with NAFLD, we observed a 23.8% prevalence of ≥F2 fibrosis, representing 12.2 million individuals, and we observed a 2.3%-9.7% prevalence of ≥F3 fibrosis, representing as many as 5.0 million adults. On multivariate regression analyses, increasing age, obesity and concurrent diabetes mellitus were associated with increased risk of ≥F3 fibrosis. CONCLUSIONS: NAFLD represents a major healthcare burden among US adults with as many as 5 million adults estimated to have NAFLD with ≥F3 fibrosis. Age and the components of the metabolic syndrome are independently associated with higher risk of fibrosis.

'The obesity paradox': a reconsideration of obesity and the risk of preterm birth.

OBJECTIVE: The association between obesity and spontaneous preterm births (sPTBs) has been shown to be influenced by obesity-attendant comorbidities. Our objective was to better understand the complex relationship of obesity and its attendant comorbidities with sPTBs. STUDY DESIGN: A retrospective analysis utilizing maternally linked hospital and birth certificate records of 2 049 196 singleton California deliveries from 2007 to 2011. Adjusted relative risks (aRRs) for sPTBs were estimated using multivariate Poisson regression modeling. RESULTS: Obese women had higher aRRs for sPTBs than their normal body mass index (BMI) controls. aRRs (95% confidence interval) increased with increasing BMI category: Obese I=1.10 (1.08 to 1.12); Obese II=1.15 (1.12 to 1.18); and Obese III=1.26 (1.22 to 1.30). When comparing only obese women without comorbidities to their normal BMI controls, aRRs reversed, that is, obese women had lower aRRs of sPTBs: Obese I=0.96 (0.94 to 0.98), Obese II=0.95 (0.91 to 0.98); and Obese III=0.98 (0.94 to 1.03). This same reversal of aRR direction was also observed among women with comorbidities: 0.92 (0.89 to 0.96); 0.89 (0.85 to 0.93); and 0.89 (0.85 to 0.93), respectively. Increasing BMI increased the aRRs for sPTBs among patients with gestational diabetes (P<0.05), while decreasing the risk among patients with chronic hypertension and pregnancy-related hypertensive disease (P<0.05). CONCLUSIONS: The obesity and preterm birth paradox is an example of what has been described as 'Simpson's Paradox'. Unmeasured confounding factors mediated by comorbidities may explain the observed protective effect of obesity upon conditioning on the presence or absence of comorbidities and thus resolve the paradox.

Hepatitis B surface antigen loss and sustained viral suppression in Asian chronic hepatitis B patients: A community-based real-world study.

Community-based real-world outcomes on effectiveness of antiviral therapies for chronic hepatitis B virus (CHB) in Asians are limited. Whether hepatitis B surface antigen (HBsAg) loss correlates with undetectable virus and alanine aminotransferase (ALT) normalization on treatment or what predicts risk of seroreversion or detectable virus after stopping therapy is unclear. We aim to evaluate rates and predictors of HBsAg loss, seroconversion, ALT normalization and undetectable HBV DNA, including HBsAg seroreversion or re-emergence of HBV DNA among Asian CHB patients. We retrospectively evaluated 1072 CHB adults on antiviral therapy at two community gastroenterology clinics from 1997 to 2015. Rates of HBsAg loss, ALT normalization, achieving undetectable HBV DNA and developing surface antibody (anti-HBs) were stratified by HBeAg status. Following HBsAg loss, HBsAg seroreversion or re-emergence of detectable HBV DNA was analysed. With median treatment of 76.7 months, the overall rate of HBsAg loss was 4.58%, with similar HBsAg loss rates between HBeAg-positive and HBeAg-negative patients (4.44% vs 4.71%, P=.85) in a predominantly Asian population (98.1%). Among HBsAg loss patients, 33.3% developed anti-HBs, 95.8% achieved undetectable virus and 66.0% normalized ALT. No significant baseline or on-treatment predictors of HBsAg loss were observed. While six patients who achieved HBsAg loss had seroreversion with re-emergence of HBsAg positivity, viral load remained undetectable, demonstrating the sustainability of viral suppression. Among a large community-based real-world cohort of Asian CHB patients treated with antiviral therapy, rate of HBsAg loss was 4.58%. Despite only 33.3% of HBsAg loss patients achieving anti-HBs, nearly all patients achieved sustained undetectable virus.

Long-term trends in chronic hepatitis B virus infection associated liver transplantation outcomes in the United States.

With effective antiviral therapies, rates of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) and decompensated liver disease requiring liver transplantation (LT) are expected to decrease. We aim to evaluate overall trends in LT waitlist registrations, waitlist survival and likelihood of receiving LT among chronic HBV patients in the United States. Using the United Network for Organ Sharing database, we retrospectively evaluated adults (age≥18) with chronic HBV (with and without HCC) listed for LT from 1992 to 1996 (Era 1) vs 1997 to 2004 (Era 2) vs 2005-2015 (Era 3). Multivariate Cox-regression models evaluated probability of waitlist survival and receiving LT. Overall, 6797 chronic HBV adults were listed for LT. While the total number of HBV patients listed for LT remained stable, the proportion of HBV patients with HCC increased from 5.4% in Era 1 to 39.0% in Era 3. Compared to Era 1, waitlist mortality was higher in Era 2 (HR: 4.55, P<.001) and Era 3 (HR: 3.63, P<.001). However, in the most recent era, waitlist mortality significantly improved (compared to 2005-2007: 2008-2011: HR: 0.74, P=.05, 95% CI: 0.55-0.99; 2012-2015: HR: 0.53, P<.001, 95% CI: 0.38-0.75). Probability of receiving LT was also lower with latter time periods (compared to 2005-2007: 2008-2011: HR: 0.77, P<.001 95% CI: 0.68-0.86; 2012-2015: HR: 0.61, P<.001, 95% CI: 0.54-0.69). Although the number of HBV patients requiring LT remained stable, the proportion of HBV patients with HCC continues to rise. The decrease in waitlist mortality and lower likelihood of LT among HBV patients may reflect the effectiveness of antiviral therapies in delaying disease progression in the current era.

Heme oxygenase-1 promoter polymorphisms: do they modulate neonatal hyperbilirubinemia?

The role of genetic factors in the modulation of serum bilirubin levels and the pathophysiology of neonatal hyperbilirubinemia is being increasingly recognized. Heme oxygenase-1 (HO-1) is the rate-limiting enzyme by which heme is catabolized to biliverdin and thence to bilirubin, with the simultaneous release of equimolar quantities of ferrous iron (Fe3+) and carbon monoxide. Polymorphisms of the HO-1 gene promoter may modulate transcriptional activity, thereby augmenting or attenuating HO-1 expression with resultant modulation of the production of bilirubin. Few studies have related these polymorphisms to neonatal bilirubin metabolism and have reported conflicting results. In this clinical review, we surveyed the role of HO-1 gene promoter polymorphisms in the control of bilirubin production and further considered their role, if any, in the pathophysiology of neonatal hyperbilirubinemia.

Upregulation of RET induces perineurial invasion of pancreatic adenocarcinoma.

Tumor spread along nerves, a phenomenon known as perineurial invasion, is common in various cancers including pancreatic ductal adenocarcinoma (PDAC). Neural invasion is associated with poor outcome, yet its mechanism remains unclear. Using the transgenic Pdx-1-Cre/KrasG12D /p53R172H (KPC) mouse model, we investigated the mechanism of neural invasion in PDAC. To detect tissue-specific factors that influence neural invasion by cancer cells, we characterized the perineurial microenvironment using a series of bone marrow transplantation (BMT) experiments in transgenic mice expressing single mutations in the Cx3cr1, GDNF and CCR2 genes. Immunolabeling of tumors in KPC mice of different ages and analysis of human cancer specimens revealed that RET expression is upregulated during PDAC tumorigenesis. BMT experiments revealed that BM-derived macrophages expressing the RET ligand GDNF are highly abundant around nerves invaded by cancer. Inhibition of perineurial macrophage recruitment, using the CSF-1R antagonist GW2580 or BMT from CCR2-deficient donors, reduced perineurial invasion. Deletion of GDNF expression by perineurial macrophages, or inhibition of RET with shRNA or a small-molecule inhibitor, reduced perineurial invasion in KPC mice with PDAC. Taken together, our findings show that RET is upregulated during pancreas tumorigenesis and its activation induces cancer perineurial invasion. Trafficking of BM-derived macrophages to the perineurial microenvironment and secretion of GDNF are essential for pancreatic cancer neural spread.

Effect of genetic variants of bilirubin metabolism on the degree of hyperbilirubinemia in African-American newborns.

OBJECTIVE: The objective of our study was to measure the effect of genetic variants of these two enzymes, UGT1A1 and SLCO1B1, in the bilirubin metabolic pathway on the degree of hyperbilirubinemia in a cohort of African-American (AA) infants from our well-baby nursery. In addition, a second objective was to document the types and frequencies of genetic variations of these enzymes in our cohort. STUDY DESIGN: A prospective study of 180 AA infants from the Well Baby Nursery of an inner city community hospital, all of whose mothers were type O pos. Sixty infants were ABO-incompatible direct antiglobulin test (DAT) pos, 60 were ABO-incompatible DAT neg and 60 were type O+. Blood for carboxyhemoglobin (COHb) and variants of the enzymes uridine diphosphoglucuronosyltransferase 1A1 and hepatic solute carrier organic anion transporter 1B1 (SLCO1B1) was drawn at the time of the infants' initial bilirubin, and the infants' precise percentile on the Bhutani nomogram was calculated. RESULTS: Variants in the two enzymes studied were quite common. In total, 21.1% were positive for a Gilbert phenotype, whereas an additional 42.4% were heterozygous for the *28 or *37 variant of UGT1A1. In total, 67.2% were homozygous for the *60 variant of the phenobarbital responsive enhancer module. In total, 41.1% were homozygous for the *1b variant of SLCO1B1, whereas an additional 12.7% were positive for the *4 variant of this gene. In total, 20.6% of infants had variations in both genes. Using logistic regression when COHbc was assessed with each of the different variants, only COHbc (P<0.0001 to 0.0004) was significantly associated with the level of hyperbilirubinemia as defined by the Bhutani nomogram. CONCLUSION: Although we have found quite a large number of genetic variants of the UGT1A1 and SLCO1B1 genes in the AA population, it does not appear that they have a significant impact on the incidence of hyperbilirubinemia among this group of infants.

Community-based real-world treatment outcomes of sofosbuvir/ledipasvir in Asians with chronic hepatitis C virus genotype 6 in the United States.

Sofosbuvir/ledipasvir (SOF/LDV) is the first all-oral ribavirin-free treatment approved for chronic hepatitis C virus (HCV) genotype 6, offering a safe and highly efficacious treatment option. Large studies evaluating real-world outcomes of this regimen are lacking. We aim to evaluate real-world treatment outcomes for HCV genotype 6. A retrospective cohort study evaluated 65 adults (age ≥18) with chronic HCV genotype 6 treated with SOF/LDV without ribavirin at a community gastroenterology clinic in the United States from November 2014 to May 2016. Rates of undetectable virus at week 4 on treatment, at end of treatment (EOT) and SVR12 were stratified by the presence of cirrhosis and prior treatment (treatment naïve vs treatment experienced). Among 65 patients with chronic HCV genotype 6 treated with SOF/LDV (52.3% male, mean age 66.3 years [SD 9.7], 41.5% cirrhosis and 15.4% treatment experienced), 97.3% had undetectable virus at week 4 on treatment, 96.9% had undetectable virus at EOT and 95.3% achieved SVR12. SVR12 was 100% in females vs 91.2% in males, P=.096, and 92.3% in patients with cirrhosis vs 97.4% in those without cirrhosis, P=.347. Resistance testing of treatment failures was attempted but unsuccessful due to lack of conforming primers to define the possible resistance mutations. Among the largest U.S. community-based real-world cohort of Asian chronic HCV genotype 6 patients treated with all-oral SOF/LDV without ribavirin, SVR12 was similar to SVR12 reported in clinical trials, confirming the safety and effectiveness of this regimen and validating current HCV genotype 6 treatment guideline recommendations.

Extreme hyperbilirubinemia and rescue exchange transfusion in California from 2007 to 2012.

OBJECTIVE: To evaluate the impact of statewide learning collaboratives that used national guidelines to manage jaundice on the serial prevalence of extreme hyperbilirubinemia (EHB, total bilirubin ⩾25 mg dl(-1)) and exchange transfusions introduced in California Perinatal Quality Care Collaborative (CPQCC) hospitals in 2007. STUDY DESIGN: Adverse outcomes were retrieved from statewide databases on re-admissions for live births ⩾35 weeks' gestation (2007 to 2012) in diverse CPQCC hospitals. Individual and cumulative select perinatal risk factors and frequencies were the outcomes measures. RESULTS: For 3 172 762 babies (2007 to 2012), 92.5% were ⩾35 weeks' gestation. Statewide EHB and exchange rates decreased from 28.2 to 15.3 and 3.6 to 1.9 per 100 000 live births, respectively. From 2007 to 2012, the trends for TB>25 mg dl(-1) rates were -0.92 per 100 000 live births per year (95% CI: -3.71 to 1.87, P=0.41 and R(2)=0.17). CONCLUSION: National guidelines complemented by statewide learning collaboratives can decrease or modify outcomes among all birth facilities and impact clinical practice behavior.

Utilization of fecal occult blood test in the acute hospital setting and its impact on clinical management and outcomes.

BACKGROUND: Despite lack of evidence supporting the use of fecal occult blood test (FOBT) in the acute hospital setting, FOBT is commonly used in the inpatient setting for reasons other than colorectal cancer (CRC) screening. AIMS: To evaluate practice trends in utilizing FOBT on inpatients and its impact on affecting clinical management and outcomes. MATERIALS AND METHODS: A cross-sectional study of consecutive adult patients undergoing FOBT from January 1, 2011 to December 31, 2011 during an acute medical admission at a large urban safety net hospital was performed. Indications for FOBT, and the impact of FOBT results on endoscopic procedures performed and clinical outcomes were assessed. The number of inpatient endoscopic procedures before and after discontinuing inpatient FOBT was also assessed. RESULTS: A total of 207 inpatient FOBTs were performed in 2011. The most common reason cited for FOBT was anemia (36%, n = 74) followed by gastrointestinal (GI) bleeding (27%, n = 55). Interestingly, 23% (n = 47) of the patients undergoing inpatient FOBT had overt GI bleeding. As expected, patients with positive FOBT were significantly more likely to undergo endoscopic examinations (P < 0.01). After discontinuing the availability of inpatient FOBT, patients were less likely to undergo endoscopic examinations [odds ratio (OR) 0.80, 95% confidence interval (CI) 0.75-0.85]. CONCLUSION: Inappropriate utilization of FOBT in the inpatient setting is common, even when the indication does not support its use. Setting limitations on inpatient FOBT may reduce the inappropriate utilization of inpatient FOBT. Quality improvement initiatives are needed to educate clinicians on the appropriate use of FOBT, which is primarily for average risk CRC screening.

Carboxyhemoglobin levels as a predictor of risk for significant hyperbilirubinemia in African-American DAT(+) infants.

OBJECTIVES: To compare the degree of hemolysis in a group of direct antiglobulin test (DAT) positive (pos) African-American (AA) infants as measured by carboxyhemoglobin corrected (COHbc) for carbon monoxide in ambient air to a similar group of DAT negative (neg) ABO incompatible infants and a group without blood group incompatibility. To determine if COHbc is a better predictor of significant hyperbilirubinemia than DAT status. STUDY DESIGN: A prospective study of 180 AA infants from the Well-Baby Nursery of an inner city community hospital, all of whose mothers were type O pos. Infants (60) were ABO incompatible DAT pos, 60 were ABO incompatible DAT neg and 60 were type O(+). Blood for COHbc was drawn at the time of the infants' initial bilirubin and the infants' precise percentile on the Bhutani nomogram was calculated. RESULT: Mean COHbc of type O(+) infants was 0.76±0.21 and 0.78±0.24% for ABO incompatible DAT neg infants (P=0.63). Mean CoHbc for the ABO incompatible DAT pos infants was 1.03±0.41% (P<0.0001 compared with both type O and DAT neg infants). Optimal cutoff on the receiver operating characteristic curve for COHbc to determine the risk for being in the Bhutani curve high risk zone was COHbc >0.90% (area under the curve(AUC) 0.8113). This was similar to the AUC of the receiver operating characteristic curve using any titer strength of DAT pos as a cutoff (0.7960). CONCLUSION: Although not greatly superior to the titer strength of DAT pos, COHbc is useful in determining if the etiology of severe hyperbilirubinemia is a hemolytic process.

Bilirubin production and hour-specific bilirubin levels.

OBJECTIVE: We assessed the relative contributions of increased bilirubin production (indexed by end-tidal carbon monoxide (CO) concentrations, corrected for ambient CO (ETCOc)) to hour-specific total bilirubin (TB) levels in healthy late preterm and term newborns. STUDY DESIGN: Post hoc analyses of concurrent ETCOc and TB (at 30±6 h of age) and follow-up TB levels at age 96±12 h and up to 168 h after birth were performed in a cohort of 641 term and late preterm infants. RESULTS: Increased bilirubin production (hour-specific ETCOc ⩾1.7 p.p.m. at age 30±6 h) was noted in ~80%, 42% and 32% of infants in the high-, intermediate- and low-risk TB zones, respectively. One infant with TB <40th percentile and ETCOc <1.7 p.p.m. developed TB ⩾95th percentile at age 168 h, probably due to decreased bilirubin elimination. CONCLUSIONS: Infants in the high-risk quartile of the hour-specific bilirubin nomogram have a higher mean bilirubin production. Infants with TB levels ⩾95th percentile without increased bilirubin production have impaired bilirubin elimination.

Sofosbuvir and simeprevir combination therapy in the setting of liver transplantation and hemodialysis.

We report safety, tolerability, and 12-week sustained virologic response with half-standard dose sofosbuvir and standard-dose simeprevir combination therapy in a hepatitis C virus genotype 1a-infected liver transplant recipient on hemodialysis - uncharted territory for sofosbuvir-based therapy. The patient was a non-responder to prior treatment with pegylated interferon plus ribavirin. Sofosbuvir efficacy was maintained despite pill-splitting and administration of half-standard dose, 200 mg per day. No drug-drug interactions were noted with tacrolimus-based immunosuppression. Laboratory tests remained stable or improved during therapy. Our observation, if reproduced in a larger study, may lead to significant improvement in clinical outcomes and cost savings in this patient population.

End-tidal carbon monoxide and hemolysis.

Hemolytic disease in newborns can result from a number of conditions, which can place such infants at an increased risk for the development of severe hyperbilirubinemia. Because the catabolism of heme produces equimolar amounts of carbon monoxide (CO) and bilirubin, measurements of end-tidal breath CO (corrected for ambient CO) or ETCOc can serve as an index of hemolysis as well as of bilirubin production from any cause. Elevated levels of ETCOc have been correlated with blood carboxyhemoglobin levels and thus hemolysis. However, the detection of hemolysis can be a clinically challenging problem in newborns. Here, we describe the importance of determining ETCOc levels and their application in identifying infants at risk for developing hyperbilirubinemia associated with hemolysis and other causes of increased bilirubin production.

Macrophages mediate gemcitabine resistance of pancreatic adenocarcinoma by upregulating cytidine deaminase.

Resistance to pharmacologic agents used in chemotherapy is common in most human carcinomas, including pancreatic ductal adenocarcinoma (PDA), which is resistant to almost all drugs, including gemcitabine, a nucleoside analog used as a first-line treatment. Poor survival rates of PDA patients have, therefore, not changed much over 4 decades. Recent data indicated that tumor-associated macrophages (TAMs), which are abundant in the microenvironment of several tumors, including PDA, secrete pro-tumorigenic factors that contribute to cancer progression and dissemination. In this study, we show for the first time that TAMs can also induce chemoresistance of PDA by reducing gemcitabine-induced apoptosis. Macrophages co-cultured with cancer cells or TAM-conditioned medium significantly reduced apoptosis and activation of the caspase-3 pathway during gemcitabine treatment. In vivo PDA models of mice, which have reduced macrophage recruitment and activation, demonstrated improved response to gemcitabine compared with controls. Similarly, inhibition of monocytes/macrophages trafficking by a CSF1-receptor antagonist GW2580 augmented the effect of gemcitabine in a transgenic mouse PDA model that was resistant to gemcitabine alone. Analysis of multiple proteins involved in gemcitabine delivery and metabolism revealed that TAMs induced upregulation of cytidine deaminase (CDA), the enzyme that metabolizes the drug following its transport into the cell. Decreasing CDA expression by PDA cells blocked the protective effect of TAMs against gemcitabine. These results provide the first evidence of a paracrine effect of TAMs, which mediates acquired resistance of cancer cells to chemotherapy. Modulation of macrophage trafficking or inhibition of CDA may offer a new strategy for augmenting the response of PDA to chemotherapy.

Protective effects of inhaled carbon monoxide in endotoxin-induced cholestasis is dependent on its kinetics.

Carbon monoxide (CO), a product of heme oxygenase (HMOX), has many beneficial biological functions and is a promising therapeutic agent for many pathological conditions. However, the kinetics of inhaled CO and its protective role in endotoxin-induced cholestasis is not fully known. Thus, our objective was to characterize the kinetics of inhaled CO and then investigate its use in early phase experimental endotoxin-induced cholestasis. Female Wistar rats were randomly divided into 4 groups: CON (control), LPS (lipopolysaccharide, 6 mg/kg), CO (250 ppm COx1h), and CO + LPS. Rats were sacrificed at 0-12 h after LPS administration. Tissues and blood were collected for liver injury markers and tissue CO distribution measurements. Livers were harvested for measurements of Hmox activity, Hmox1 mRNA expression, cytokines (IL10, IL6, TNF), and bile lipid and pigment transporters. Half-lives of CO in spleen, blood, heart, brain, kidney, liver, and lungs were 2.4 ± 1.5, 2.3 ± 0.8, 1.8 ± 1.6, 1.5 ± 1.2, 1.1 ± 1.1, 0.6 ± 0.3, 0.6 ± 0.2 h, respectively. CO treatment increased liver IL10 mRNA and decreased TNF expression 1 h after LPS treatment and prevented the down-regulation of bile acid and bilirubin hepatic transporters (Slc10a1, Abcb11, and Abcc2, p < 0.05), an effect closely related to the kinetics. The protective effect of CO against cholestatic liver injury persisted even 12 h after CO exposure, as shown by attenuation of serum cholestatic markers in CO-treated animals. CO exposure substantially attenuated endotoxin-induced cholestatic liver injury and was directly related to the kinetics of inhaled CO. This data underscores the importance of the kinetics of inhaled CO for the proper design of experimental and clinical studies of using CO as a treatment strategy.