Sustained activation of 12/15 lipoxygenase (12/15 LOX) contributes to impaired renal recovery post ischemic injury in male SHR compared to females

BACKGROUND

Acute kidney injury (AKI) due to ischemia-reperfusion (IR) is a serious and frequent complication in clinical settings, and mortality rates remain high. There are well established sex differences in renal IR, with males exhibiting greater injury following an ischemic insult compared to females. We recently reported that males have impaired renal recovery from ischemic injury vs. females. However, the mechanisms mediating sex differences in renal recovery from IR injury remain poorly understood. Elevated 12/15 lipoxygenase (LOX) activity has been reported to contribute to the progression of numerous kidney diseases. The goal of the current study was to test the hypothesis that enhanced activation of 12/15 LOX contributes to impaired recovery post-IR in males vs. females.

METHODS

13-week-old male and female spontaneously hypertensive rats (SHR) were randomized to sham or 30-minute warm bilateral IR surgery. Additional male and female SHR were randomized to treatment with vehicle or the specific 12/15 LOX inhibitor ML355 1 h prior to sham/IR surgery, and every other day following up to 7-days post-IR. Blood was collected from all rats 1-and 7-days post-IR. Kidneys were harvested 7-days post-IR and processed for biochemical, histological, and Western blot analysis. 12/15 LOX metabolites 12 and 15 HETE were measured in kidney samples by liquid chromatography-mass spectrometry (LC/MS).

RESULTS

Male SHR exhibited delayed recovery of renal function post-IR vs. male sham and female IR rats. Delayed recovery in males was associated with activation of renal 12/15 LOX, increased renal 12-HETE, enhanced endoplasmic reticulum (ER) stress, lipid peroxidation, renal cell death and inflammation compared to females 7-days post-IR. Treatment of male SHR with ML355 lowered levels of 12-HETE and resulted in reduced renal lipid peroxidation, ER stress, tubular cell death and inflammation 7-days post-IR with enhanced recovery of renal function compared to vehicle-treated IR male rats. ML355 treatment did not alter IR-induced increases in plasma creatinine in females, however, tubular injury and cell death were attenuated in ML355 treated females compared to vehicle-treated rats 7 days post-IR.

CONCLUSION

Our data demonstrate that sustained activation 12/15 LOX contributes to impaired renal recovery post ischemic injury in male and female SHR, although males are more susceptible on this mechanism than females.

Association of vaspin rs2236242 with type 2 diabetes mellitus and obesity: a meta-analysis of case-control studies

Background

Elevated circulating vaspin levels is linked with type 2 diabetes mellitus (T2DM) and obesity. The genetic basis of the association between vaspin rs2236242 and T2DM and obesity is still being investigated. We executed a meta-analysis to evaluate the magnitude of effect caused by vaspin rs2236242 on T2DM and obesity.

Methods

We searched Pubmed, Embase, MEDLINE, Scopus, Web of Science, and Google Scholar for relevant articles published up to 19 February 2022. Data were extracted and summary estimates of the association between vaspin rs2236242 and T2DM and obesity were assessed. Odds ratios (ORs) and confidence intervals (CIs) were used to measure the effect.

Results

This meta-analysis included 2206 cases and 2715 controls in the T2DM cohort, meanwhile 271 cases and 444 controls in the obesity cohort. The pooled estimates revealed no link between vaspin rs2236242 and T2DM, but allele-A was significantly higher in the controls of the obesity cohort, showing that this single nucleotide polymorphism (SNP) has a reduced obesity risk effect. Sensitivity analysis revealed no studies that would modify the estimates or the heterogeneity. Begg and Mazumdar's and Egger's tests indicated no substantial publication bias.

Conclusion

Our meta-analysis provides evidence of significant association between vaspin rs2236242 and reduced risk of obesity but not T2DM.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-022-01119-8.

Circular RNAs and acute kidney injury: a clinical science commentary on Cao et al

Acute kidney injury (AKI) remains a significant clinical problem with a high mortality rate. Thus, the need for early recognition and treatment of AKI is an important goal. Clinical Science has a history of publishing high impact work across a breadth of scientific disciplines to improve understanding of disease mechanisms, including nephrology. This commentary spotlights a paper from more recent history that is highly cited. The work focuses on the mechanistic role of circular RNA in the pathobiology of AKI using approaches that include both in vivo experimental models and human cell culture experiments to delineate a potentially novel cellular pathway.

Perinatal intermittent hypoxia increases early susceptibility to ANG II-induced hypertension in adult male but not in female Sprague-Dawley rats

Prenatal, perinatal, and adulthood exposure to chronic intermittent hypoxia (IH) increases blood pressure in rodents. Males exposed to chronic IH have higher blood pressure versus females. However, it is unknown if this same-sex difference exists with acute perinatal IH. We tested the hypothesis that acute perinatal IH increases baseline blood pressure and enhances sensitivity to angiotensin II (ANG II)-induced hypertension in male Sprague-Dawley rats. Male and female pups were randomized to control (room air) or IH (10 min of ∼10% O2 for 3 times/day) for the first 8 days of life. IH decreased oxygen saturation, as confirmed via a pulse oximeter. Pups were weaned at postnatal day 21. Blood pressure was measured via telemetry beginning at 14 wk of age and analyzed separately into light and dark phases to assess circadian rhythm. Osmotic minipumps to deliver ANG II were implanted at 15 wk of age. Perinatal IH exposure did not alter baseline blood pressure. One week of ANG II treatment increased blood pressure in light and dark periods in males exposed to IH versus control; there was no effect in females. Blood pressure among the groups was comparable following 2 wk of ANG II infusion. Perinatal IH did not change the circadian rhythm. Following ANG II treatment, indexes of renal injury were measured. Perinatal IH did not alter kidney size, structure, nephron number, or creatinine clearance. These data indicate that acute perinatal IH enhances early ANG II-induced hypertension in males, independent of nephron loss or decreases in body weight or kidney function.NEW & NOTEWORTHY The impact of acute intermittent hypoxia (IH) in early life on blood pressure in adulthood is unknown. This study used a new model exposing female and male rat pups to acute IH in the first 8 days of life, without exposing the dam. Although baseline blood pressure was not altered in adulthood, IH increased susceptibility to angiotensin II hypertension only in males, supporting increased susceptibility of males exposed to IH to a second cardiovascular stressor.

Impact of urinary calcium excretion on kidney, bone, and cardiovascular systems in patients with bone biopsy proven osteoporosis: a longitudinal long-term follow-up study

The impact of urine calcium on kidney, bone, and cardiovascular systems in osteoporosis is not well-known. In this 7-year-follow-up study, high urine calcium did not affect kidney function but increased risk of kidney stones, while low urine calcium increased cardiovascular diseases. Maintaining normal urine calcium is beneficial for bone health.

PURPOSE

Hypercalciuria is common in patients with osteoporosis. However, the long-term effect of urinary calcium excretion (UCaE) on patients' health is not well-examined. The current study aims to assess the impact of UCaE on kidney, bone, and cardiovascular outcomes in patients with bone biopsy proven osteoporosis.

METHODS

Longitudinal study of all patients with osteoporosis who underwent bone biopsy and 24-h urine collection between 2008 and 2015 in the University of Kentucky. DXA scans, serum markers, kidney function, and cardiovascular events were recorded until last clinic visit in 2021. Exclusion criteria were secondary osteoporosis or conditions that might substantially impact UCaE. The significant results in univariate analysis were confirmed in multi-variable regression models involving clinically important covariates that might impact patients' outcomes.

RESULTS

Study included 230 patients with mean follow-up of 7.2 ± 2.9 years. The mean age was 61 years, and the mean eGFR at baseline was 85 ± 19 ml/min/1.73 m². Low bone turnover (LBT) was present in 57% and high bone turnover (HBT) in 43% of patients. Hypercalciuria was found in one-third of patients with no difference between LTB and HTB. UCaE correlated positively with eGFR but did not affect the rate of eGFR decline over time. Higher UCaE predicted kidney stones development. We observed U-shaped effect of UCaE on bone health. Hypercalciuria predicted loss of BMD at all sites, but also hypocalciuria was associated with higher loss in total hip BMD. Upper limb fractures were the most observed fractures, and their incidence was higher in patients with hyper- or hypo-calciuria. Lower UCaE independently predicted development of major adverse cardiac events (MACE) and cardiovascular disease (CVD).

CONCLUSION

UCaE correlated with eGFR but it did not affect the change of eGFR over time. Patients with normal UCaE had lower incidence of upper limb fractures and less reduction in BMD. Low UCaE predicted MACE and CVD.

S-100 Negative Granular Cell Tumor of Oral Cavity with Aggressive Clinical Behavior

Introduction/Objective

Granular cell tumors (GCTs) are neoplasms with neuroectodermal (Schwann cell) differentiation that is typically benign and cured by surgical excision. These tumors characteristically display strong expression of S-100 protein. Similar tumors without expression of S-100 protein are called “S-100 negative granular cell tumors.” The few reported cases of S-100 negative GCT in the oral cavity describe indolent clinical behavior. We report a case of a 49-year-old male with recurrent S-100 negative GCT in the oral cavity.

Methods/Case Report

The patient presented initially with a mass in the hard palate, which was resected and diagnosed as an S-100 negative GCT. One year later, the patient developed severe epistaxis and anemia (hemoglobin 7.2 g/dL). A large tumor of the hard palate was the source of bleeding. It was resected and diagnosed as recurrent S-100 negative GCT. Histologically, this tumor consists of small nests of epithelioid to spindled cells with moderately abundant granular eosinophilic cytoplasm, round central nuclei with vesicular chromatin and distinct eosinophilic nucleoli, and significant mitotic activity. The cells are immunoreactive for SOX10 and negative for S-100, melan-A, keratin AE1/AE3, p40, synaptophysin, smooth muscle actin, desmin, and myogenin.

Results (if a Case Study enter NA)

N/A

Conclusion

S-100 negative GCTs are rare, and only a few case reports describe their involvement in the oral cavity. We report this case because of its rarity and aggressive clinical behavior. Recognition of this entity and its potential for locally aggressive growth is important. Management of this tumor by complete excision seems advisable.

Sex differences in apoptosis do not contribute to sex differences in blood pressure or renal T cells in spontaneously hypertensive rats

Apoptosis is a physiological and anti-inflammatory form of cell death that is indispensable for normal physiology and homeostasis. Several studies have reported aberrant activation of apoptosis in various tissues at the onset of hypertension. However, the functional significance of apoptosis during essential hypertension remains largely undefined. The current study was designed to test the hypothesis that apoptosis contributes to sex differences in blood pressure and the T cell profile in spontaneously hypertensive rats (SHR). Apoptosis was measured in kidney, aorta and spleen of 13-week-old adult hypertensive male and female SHR. Female SHR had greater renal and aortic apoptosis compared to age-matched males; apoptosis in the spleen was comparable between the sexes. Based on well-established sex differences in hypertension, we tested the hypothesis that greater apoptosis in female SHR contributes to the lower BP and pro-inflammatory profile compared to males. Male and female SHR were randomized to receive vehicle or ZVAD-FMK, a cell permeable pan-caspase inhibitor, in established hypertension from 13 to 15 weeks of age or at the onset of hypertension from 6 to 12 weeks or age. Treatment with ZVAD-FMK lowered renal apoptosis in both studies, yet neither BP nor renal T cells were altered in either male or female SHR. These results suggest that apoptosis does not contribute to the control or maintenance of BP in male or female SHR or sex differences in renal T cells.

Genetic Deletion of LRP5 and LRP6 in Macrophages Exacerbates Colitis-Associated Systemic Inflammation and Kidney Injury in Response to Intestinal Commensal Microbiota

Extraintestinal manifestations are common in inflammatory bowel disease and involve several organs, including the kidney. However, the mechanisms responsible for renal manifestation in inflammatory bowel disease are not known. In this study, we show that the Wnt-lipoprotein receptor-related proteins 5 and 6 (LRP5/6) signaling pathway in macrophages plays a critical role in regulating colitis-associated systemic inflammation and renal injury in a murine dextran sodium sulfate-induced colitis model. Conditional deletion of the Wnt coreceptors LRP5/6 in macrophages in mice results in enhanced susceptibility to dextran sodium sulfate colitis-induced systemic inflammation and acute kidney injury (AKI). Furthermore, our studies show that aggravated colitis-associated systemic inflammation and AKI observed in LRP5/6^LysM mice are due to increased bacterial translocation to extraintestinal sites and microbiota-dependent increased proinflammatory cytokine levels in the kidney. Conversely, depletion of the gut microbiota mitigated colitis-associated systemic inflammation and AKI in LRP5/6^LysM mice. Mechanistically, LRP5/6-deficient macrophages were hyperresponsive to TLR ligands and produced higher levels of proinflammatory cytokines, which are associated with increased activation of MAPKs. These results reveal how the Wnt-LRP5/6 signaling in macrophages controls colitis-induced systemic inflammation and AKI.

Netrin-1 Overexpression Induces Polycystic Kidney Disease: A Novel Mechanism Contributing to Cystogenesis in Autosomal Dominant Polycystic Kidney Disease

Despite recent advances in understanding the pathogenesis of polycystic kidney disease (PKD), the underlying molecular mechanisms involved in cystogenesis are not fully understood. This study describes a novel pathway involved in cyst formation. Transgenic mice overexpressing netrin-1 in proximal tubular cells showed increased production and urinary excretion of netrin-1. Although no cysts were detectable immediately after birth, numerous small cysts were evident by the age of 4 weeks, and disease was accelerated along with age. Surprisingly, cyst formation in the kidney was restricted to male mice, with 80% penetrance. However, ovariectomy induced kidney cyst growth in netrin-1-overexpressing female mice. Cyst development in males was associated with albuminuria and polyuria and increased cAMP excretion in netrin-1 transgenic mice. Netrin-1 overexpression significantly increased extracellular signal-regulated kinase and focal adhesion kinase phosphorylation and vimentin expression. Interestingly, p53 expression was increased but in an inactive form. Furthermore, netrin-1 expression was increased in cystic epithelia and urine of various rodent models of PKD. siRNA-mediated suppression of netrin-1 significantly reduced cyst growth and improved kidney function in netrin-1 transgenic mice and in two genetic animal models of PKD. Together, these data demonstrate that netrin-1 up-regulation induced cyst formation in autosomal dominant PKD.

Sex Differences in TLR4 Expression in SHR Do Not Contribute to Sex Differences in Blood Pressure or the Renal T cell Profile

Hypertension is a primary risk factor for the development of cardiovascular disease. Mechanisms controlling blood pressure (BP) in men and women are still being investigated, however, there is increasing evidence supporting a role for the innate immune system. Specifically, Toll-like receptors (TLR), and TLR4 in particular, have been implicated in the development of hypertension in male spontaneously hypertensive rats (SHR). Despite established sex differences in BP control and inflammatory markers in hypertensive males and females, little is known regarding the role of TLR4 in hypertension in females. Our hypotheses were that male SHR have greater TLR4 expression compared to females, and that sex differences in TLR4 contribute to sex differences in BP and the T cell profile. To test these hypotheses, initial studies measured renal TLR4 protein expression in 13-week old male and female SHR. Additional SHR were implanted with telemetry devices and randomized to treatment with either IgG or TLR4 neutralizing antibodies. Untreated control male SHR have greater TLR4 protein expression in the kidney compared to females. However, treatment with TLR4 neutralizing antibody for 2 weeks did not significantly alter BP in either male or female SHR. Interestingly, neutralization of TLR4 increased renal CD3⁺ T cells in female SHR, with no alteration in CD4⁺ T cells or CD8⁺ T cells in either sex. Taken together, our data indicates that although male SHR have greater renal TLR4 expression than females, TLR4 does not contribute to the higher BP and more pro-inflammatory renal T cell prolife in males vs. females.

Malignant Gastrointestinal Neuroectodermal Tumor: a case report and a review of the literature

Introduction/Objective

Malignant gastrointestinal neuroectodermal tumor (GNET) is a rare soft tissue tumor arising in the wall of the gastrointestinal tract. The GNET was first described as an osteoclast rich tumor of the gastrointestinal tract with features resembling clear cell sarcoma, with only few cases reported in the literature.

Methods/Case Report

We report a case of a 71-year-old man with a past medical history of hypertension, hyperlipidemia, and benign prostatic hyperplasia presented with complaints of dyspnea, dizziness, fatigue, black stools, and a recent syncopal episode. Laboratory testing revealed anemia (HB 5.4 g/dL). Esophagogastroduodenoscopy demonstrated a submucosal gastric mass. An abdominal CT scan confirmed a 7.8 cm mass along the gastric cardia and fundus.

Results (if a Case Study enter NA)

Biopsy rendered a gastrointestinal neuroectodermal tumor (GNET). Microscopically, the tumor cells were spindle with eosinophilic cytoplasm and arranged in fascicules. They were positive for CD56, CD99, and Fli-1, synaptophysin, and negative for chromogranin, TTF-1, SMA, desmin, CD34, EMA, pan-cytokeratin, and lymphoid markers. Two months later, further imaging confirmed metastasis to the liver and spleen. GNETs typically arise within the muscularis propria of the gastrointestinal tract and often extend into the submucosa and subserosa.

Conclusion

The most important differential of GNET is the clear cell sarcoma of the gastrointestinal tract (CCS-GI). Both share similar morphological as well as molecular features and show S100 positivity; however, the lack of melanocytic differentiation in GNET distinguishes it from CCS-GI. Both typically show rearrangements of the EWSR1 gene, with t(12;22) (q13;q12) EWSR1-ATF1 or t(2;22)(q34;q12) EWSR1-CREB1 fusions. Pathologists should be aware of GNET diagnostic entity due to its aggressive behavior and high rate of recurrence and mortality even after complete resection.

Cell viability and electrical response of breast cancer cell treated in aqueous graphene oxide solution deposition on interdigitated electrode

Breast cancer is one of the most reported cancers that can lead to death. Despite the advances in diagnosis and treatment procedures, the possibility of cancer recurrences is still high in many cases. With that in consideration, researchers from all over the world are showing interest in the unique features of Graphene oxide (GO), such as its excellent and versatile physicochemical properties, to explore further its potential and benefits towards breast cancer cell treatment. In this study, the cell viability and electrical response of GO, in terms of resistivity and impedance towards the breast cancer cells (MCF7) and normal breast cells (MCF10a), were investigated by varying the pH and concentration of GO. Firstly, the numbers of MCF7 and MCF10a were measured after being treated with GO for 24 and 48 h. Next, the electrical responses of these cells were evaluated by using interdigitated gold electrodes (IDEs) that are connected to an LCR meter. Based on the results obtained, as the pH of GO increased from pH 5 to pH 7, the number of viable MCF7 cells decreased while the number of viable MCF10a slightly increased after the incubation period of 48 h. Similarly, the MCF7 also experienced higher cytotoxicity effects when treated with GO concentrations of more than 25 µg/mL. The findings from the electrical characterization of the cells observed that the number of viable cells has corresponded to the impedance of the cells. The electrical impedance of MCF7 decreased as the number of highly insulating viable cell membranes decreased. But in contrast, the electrical impedance of MCF10a increased as the number of highly insulating viable cell membranes increased. Hence, it can be deduced that the GO with higher pH and concentration influence the MCF7 cancer cell line and MCF10a normal breast cell.

Splenectomy increases blood pressure and abolishes sex differences in renal T-regulatory cells in spontaneously hypertensive rats

Over the past decade there has been increasing support for a role of the immune system in the development of hypertension. Our lab has previously reported that female spontaneously hypertensive rats (SHRs) have a blood pressure (BP)-dependent increase in anti-inflammatory renal regulatory T cells (Tregs), corresponding to lower BP compared with males. However, little is known regarding the mechanism for greater renal Tregs in females. The current study was designed to test the hypothesis that the greater relative abundance of renal Tregs in female SHR is due to greater Treg production. To test this hypothesis, T cell profiles were measured in the spleen by flow cytometry in male and female SHR at 5 and 14 weeks of age. Splenic Tregs did not differ between males and females, suggesting sex differences in renal Tregs is not due to differences in production. To assess the role of the spleen in sex differences in renal Tregs and BP control, rats were randomized to receive sham surgery (CON) or splenectomy (SPLNX) at 12 weeks of age and implanted with telemeters to measure BP. After 2 weeks, kidneys were harvested for flow cytometric analysis of T cells. Splenectomy increased BP in both sexes after 2 weeks. Renal Tregs decreased in both sexes after splenectomy, abolishing the sex differences in renal Tregs. In conclusion, splenic Tregs were comparable in male and female SHRs, suggesting that sex differences in renal Tregs is due to differences in renal Treg recruitment, not Treg production.

1268 Pathology Pick up Rate in Routine Preoperative Endoscopy and its Impact on Patients Undergoing Gastric Bypass Surgery

Aim

Preoperative OGD in patients undergoing bariatric surgery, has been a subject for debate for decades. The aim of this study is to evaluate the pathology pick up rate in routine preoperative endoscopy in patients undergoing Gastric Bypass surgery (LRYGB) in our unit.

Method

Retrospective review of patients’ records who underwent LRYBG in our unit from February 2009 to March 2020. Patients were divided into two groups according to the presence or absence of symptoms prior to bariatric surgery: Group A (Asymptomatic) and Group B (Symptomatic). Data from prospectively kept electronic OGD reports, CLO test results, histology reports and the changes in management plan were collected and analysed.

Results

114 patients were included in the analysis, 85 (74.56%) were in group A and 29 in group B. OGD detected pathology in 34 patients in group A and 21 in group B (p = 0.004). Those included hiatus hernia (HH) (17.65% group A, 44.83% group B, p = 0.006); stomach ulcer (7.06% group A, 3.45% group B, p = 0.676), H.pylori infection (12.86% group A, 29.41% group B). This led to change of management in 22 patients in group A and 12 of group B (p = 0.157) excluding PPI prescription. Those changes included H.pylori eradication (10.59% group A, 17.24% group B, p = 0.153), HH repair (3.53% group A, 24.14% group B, p = 0.002). There was no cancellation or change in bariatric surgery offered in both groups.

Conclusions

Preoperative OGD has only significantly impacted the bariatric patient’s pathway in symptomatic patients. However, in Asymptomatic patients, OGD could be replaced by cheaper and non-invasive alternatives.

A73 PERFORMANCE OF ASGE AND ESGE CRITERIA FOR RISK STRATIFICATION FOR CHOLEDOCHOLITHIASIS IN A REAL-WORLD SETTING

Background

Choledocholithiasis (CDL) is a common clinical entity and can lead to serious complications, such as pancreatitis or ascending cholangitis. Endoscopic retrograde cholangio-pancreatography (ERCP) is generally the first-line procedure for definitive management of CDL. ERCP has well-established adverse events. Given the risks, patients can be stratified by likelihood of finding CDL on ERCP, thus potentially avoiding an unnecessary procedure in low probability patients. There are three commonly used criteria for this – the American Society for Gastrointestinal Endoscopy (ASGE) 2010 criteria, the ASGE 2019 criteria, and the European Society of Gastrointestinal Endoscopy (ESGE) 2019 criteria. These criteria use a mixture of biliary imaging, clinical condition, and liver biochemistry to stratify patients into low, intermediate, and high probability for CDL.

Aims

To test the performance characteristics of the ASGE 2010, ASGE 2019, and ESGE 2019 criteria for probability of CDL on a real-world sample.

Methods

We identified all adult patients who had ERCP done at our local centre for suspected CDL between 2012/01/01 and 2018/10/07. A sample of 1000 cases were chosen. We obtained the patients’ pre-procedural liver biochemistries, pre-procedural imaging in the preceding 6 months, and their ERCP reports. We used a semi-automated algorithm to determine confirmation of CDL. We inferred clinical gallstone pancreatitis using the surrogate of serum lipase at or greater than three times upper limit of normal. We could not capture clinical ascending cholangitis from the collected data. We stratified each patient according to the three guidelines and calculated their performance characteristics.

Results

After manually reviewing visits with incomplete ERCP or repeat ERCP, we analyzed 879 ERCP visits. There were 622 with stone or sludge found on ERCP. The performance characteristics of the high-probability and intermediate-probability criteria of the three guidelines are listed in the table below.

Conclusions

Our results for the 2010 ASGE guidelines high probability patients are in keeping with previous validation studies. There have been only one validation study each of the 2019 ASGE guidelines and the 2019 ESGE guidelines, and our results are different in sensitivity and negative predictive value. Future directions in refining these risk stratification tools are needed, and our project in ongoing in assessing the additional value of trends in liver biochemistry.

Funding Agencies

None

N-Methyl-D-aspartate receptor activation, novel mechanism of homocysteine-induced blood-retinal barrier dysfunction

Elevated levels of amino acid homocysteine (Hcy) recognized as hyperhomocysteinemia (HHcy) was reported in several human visual disorders, such as diabetic retinopathy (DR) and age-related macular degeneration (AMD). Breakdown of blood-retinal barrier (BRB) is concomitant with vision loss in DR and AMD. We previously reported that HHcy alters BRB. Here, we tested the hypothesis that HHcy alters BRB via activation of N-methyl-D-aspartate receptor (NMDAR). Human retinal endothelial cells subjected to high level of Hcy and mouse model of HHcy were used. We injected Hcy intravitreal and used a mouse model of HHcy that lacks cystathionine-β-synthase (CBS). RT-PCR, western blot, and immunofluorescence showed that retinal endothelial cells (RECs) express NMDAR at the gene and protein levels both in vitro and in vivo and this was increased by HHcy. We assessed BRB function and retinal morphology using fluorescein angiogram and optical coherence tomography (OCT) under HHcy with and without pharmacological inhibition of NMDAR by (MK801) or in mice lacking endothelial NMDAR (NMDARE-/- mouse). Additionally, retinal albumin leakage and tight junction proteins ZO-1 and occludin were assessed by western blotting analysis. Inhibition or elimination of NMDAR was able to improve the altered retinal hyperpermeability and morphology under HHcy as indicated by significant decrease in retinal albumin leakage and restoration of tight junction proteins ZO-1 and occludin. Our findings underscore a potential role for endothelial NMDAR in mediating Hcy-induced breakdown of BRB and subsequently as a potential therapeutic target in retinal diseases associated with HHcy such as DR and AMD. KEY MESSAGES: • Elevated levels of homocysteine (Hcy) are defined as hyperhomocysteinemia (HHcy). • HHcy is implicated in diabetic retinopathy and age-related macular degeneration. • HHcy alters BRB via activation of N-methyl-D-aspartate receptor.

Ultrasound measurement of change in kidney volume is a sensitive indicator of severity of renal parenchymal injury

Noninvasive determination of the severity of parenchymal injury in acute kidney injury remains challenging. Edema is an early pathological process following injury, which may correlate with changes in kidney volume. The goal of the present study was to test the hypothesis that "increases in kidney volume measured in vivo using ultrasound correlate with the degree of renal parenchymal injury." Ischemia-reperfusion (IR) of varying length was used to produce graded tissue injury. We first determined 1) whether regional kidney volume in rats varied with the severity (0, 15, 30, and 45 min) of warm bilateral IR and 2) whether this correlated with tubular injury score. We then determined whether these changes could be measured in vivo using three-dimensional ultrasound. Finally, we evaluated cumulative changes in kidney volume up to 14 days post-IR in rats to determine whether changes in renal volume were predictive of latent tubular injury following recovery of filtration. Experiments concluded that noninvasive ultrasound measurements of change in kidney volume over 2 wk are predictive of tubular injury following IR even in animals in which plasma creatinine was not elevated. We conclude that ultrasound measurements of volume are a sensitive, noninvasive marker of tissue injury in rats and that the use of three-dimensional ultrasound measurements may provide useful information regarding the timing, severity, and recovery from renal tissue injury in experimental studies.

Hypertensive female Sprague-Dawley rats require an intact nitric oxide synthase system for compensatory increases in renal regulatory T cells

We have previously shown that hypertensive female rats have more regulatory T cells (Tregs), which contribute more to blood pressure (BP) control in female versus male rats. Based on known protective properties of Tregs, the goal of the present study was to investigate the mechanisms by which female rats maintain Tregs. The present study was designed to 1) compare the impact of three hypertension models on the percentage of renal Tregs and 2) test the hypothesis that nitric oxide synthase (NOS) inhibition prevents increases in renal Tregs and exacerbates renal damage in female Sprague-Dawley rats. Rats (11-14 wk old) were randomized to one of the following four groups: control, norepinephrine (NE) infusion, angiotensin II infusion, or the NOS inhibitor N^ω-nitro-l-arginine methyl ester (l-NAME) in drinking water. BP was measured via tail cuff. After 2 wk of treatment, kidneys were isolated and processed to measure Tregs via flow cytometric analysis and renal injury via urinary albumin excretion, plasma creatinine, and histological analyses. Hypertensive treatments increased BP in all experimental animals. Increases in BP in norepinephrine-and angiotensin II-treated rats were associated with increases in renal Tregs versus control. In contrast, l-NAME treatment decreased Tregs compared with all groups. l-NAME treatment modestly increased albumin excretion. However, plasma creatinine was comparable among the groups, and there was no histological evidence of glomerular or tubular injury. This study provides insights into the mechanisms regulating renal Tregs and supports that an intact NOS system is crucial for female rats to have BP-related increases in renal Tregs.

Greater T Regulatory Cells in Females Attenuate DOCA-Salt-Induced Increases in Blood Pressure Versus Males

Hypertension is the most common risk factor for cardiovascular disease, causing over 18 million deaths a year. Although the mechanisms controlling blood pressure (BP) in either sex remain largely unknown, T cells play a critical role in the development of hypertension. Further evidence supports a role for the immune system in contributing to sex differences in hypertension. The goal of the current study was to first, determine the impact of sex on the renal T-cell profiles in DOCA-salt hypertensive males and females and second, test the hypothesis that greater numbers of T regulatory cells (Tregs) in females protect against DOCA-salt-induced increases in BP and kidney injury. Male rats displayed greater increases in BP than females following 3 weeks of DOCA-salt treatment, although increases in renal injury were comparable between the sexes. DOCA-salt treatment resulted in an increase in proinflammatory T cells in both sexes; however, females had more anti-inflammatory Tregs than males. Additional male and female DOCA-salt rats were treated with anti-CD25 to decrease Tregs. Decreasing Tregs significantly increased BP only in females, thereby abolishing the sex difference in the BP response to DOCA-salt. This data supports the hypothesis that Tregs protect against the development of hypertension and are particularly important for the control of BP in females.

A272 THE CANADIAN DIRECT OBSERVATION OF PROCEDURAL SKILLS (CANDOPS) TOOL FOR ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY: A MULTI-CENTRE PROSPECTIVE STUDY

Background

Previous studies have demonstrated that many graduating trainees may not have all of the skills needed to independently practice endoscopic retrograde cholangiopancreatography (ERCP) safely and effectively. As a part of competency-based learning curriculum development, it is essential to provide formative feedback to trainees and ensure they acquire the knowledge and skills for independent practice.

Aims

To assess the performance of advanced endoscopy trainees across Canada using the Canadian Direct Observation of Procedural Skills (CanDOPS) ERCP assessment tool. Procedural items evaluated include both technical (cannulation, sphincterotomy, stone extraction, tissue sampling, and stent placement) and non-technical (leadership, communication and teamwork, judgment and decision making) skills.

Methods

We conducted a prospective national multi-centre prospective study. Advanced endoscopy trainees with at least two years of gastroenterology training or five years of general surgery in North America and minimal experience performing ERCPs (less than 100 ERCP procedures) were invited to participate. The CanDOPS tool was used to measure every fifth ERCP performed by trainees over a 12-month fellowship training period. ERCPs were evaluated by experienced staff endoscopists at each study site under standard clinical protocol. Cumulative sum (CUSUM) analyses were used to generate learning curves.

Results

The data from five Canadian sites and 11 trainees participated in the study. A total of 261ERCP evaluations were completed. Median number of evaluations by site and trainee was 49 (IQR 31–76) and 15 (IQR 11–45). Median number of cases trainees performed prior to their ERCP training was 50 (IQR 25–400). There was a significant improvement in almost all scores over time, including selective cannulation, sphincterotomy, biliary stenting and all non-technical skills (P<0.01). CUSUM analyses using acceptable and unacceptable failure rates of 20% and 50% demonstrated trainees achieved competency for most measures in their final month of their training. Competency in tissue sampling was not achieved within a one-year training period.

Conclusions

This is the first ERCP performance evaluation tool that examines multiple technical and non-technical aspects of the procedure. Although trainee ERCP skills do improve during their training period, there exists a notable variability in time to competency for the different skills measured using the CanDOPS tool. Large prospective research is required to determine if competency is achieved using more stringent definitions of ERCP competency and to determine factors associated with reaching competency.

Funding Agencies

None

A279 EUS-GUIDED BILIARY DRAINAGE IN MALIGNANT DISTAL BILIARY OBSTRUCTION: AN INTERNATIONAL SURVEY TO IDENTIFY BARRIERS OF TECHNOLOGY IMPLEMENTATION

Background

Endoscopic ultrasound-guided biliary drainage (EUS-BD) is a promising alternative to endoscopic retrograde cholangiopancreatography (ERCP) in malignant distal biliary obstruction (MDBO). Recent small randomized controlled trials comparing EUS-BD with ERCP suggest that EUS-BD achieves a similar technical success rate and safety profile while potentially being associated with lower rates of stent dysfunction However, its application in clinical practice has been impeded by various undefined barriers.

Aims

To evaluate the current practice of EUS-BD and the determinants for its clinical implementation in MDBO.

Methods

An online survey was generated using Google Forms. Five endoscopy societies have distributed the survey as of October 10th, 2019. Survey questions measured participant characteristics, EUS-BD in different clinical scenarios, and potential barriers to implementation. Descriptive statistics were calculated using frequencies, chi-square statistics were used for inferential analysis, and a standard step-wise multivariable analysis was performed to identify independent variables for and against the use of EUS-BD.

Results

To date, 102 physicians have participated in the survey (response rate 7.97%). The majority of participants are from North America (39.2%), Asia (31.4%), and Europe (19.6%). Most participants are gastroenterologists with formal therapeutic endoscopy training (66.7%), though only 28.4% have received EUS-BD training. In unresectable cancer, 85.1% of respondents favoured EUS-BD over percutaneous biliary drainage following ERCP failure (p<0.0001), while in borderline resectable disease, 72.3% preferred EUS-BD. On multivariable analysis, male gender, formal training in EUS-BD, and unresectable cancer were independent variables for the use of EUS-BD. Conversely, independent discouraging factors for EUS-BD included fear of adverse events, limited high-quality data, lack of local expertise, and inadequate access to EUS technology.

Conclusions

In this international survey, it appears that EUS-BD is gaining traction, especially in the setting of unresectable disease following ERCP failure. However, barriers to implementation include the lack of high-quality data, fear for adverse events, limited experts in the field, and inadequate access to EUS technology. This suggest the need for high-quality clinical trials, increased endoscopist training in this field, and further technology development in EUS-BD in order to increase its uptake in clinical practice.

Funding Agencies

None

Abstract P3035: Role of T Cells in Sex Differences in Blood Pressure Elevation and Adipose Tissue Expansion Following Chronic High Fat Diet Feeding in Dahl Rats

Diets high in saturated fats are increasingly linked to the development of hypertension, yet the mechanisms by which high saturated fat diet (HFD) increases blood pressure remain unclear. Although young women are typically protected from hypertension relative to age-matched men, recent studies suggest that the cardiovascular protection in young women is compromised by chronic consumption of a HFD. We hypothesize that chronic HFD treatment causes a greater increase in blood pressure in females via sex-specific activation and recruitment of T cells and adipocyte expansion. Male and female Dahl rats (n=4-5) were placed on HFD at 8 wks of age. After 4 wks of HFD, blood pressure (BP) significantly increased in male and female Dahl rats to a comparable degree. Although BP continued to increase over the course of 10 wks of HFD treatment, female rats have a greater increases in BP (~40 mmHg increase in BP) after 10 weeks of HFD vs. males (~20 mmHg increase in BP). Fat pad weight and adipose tissue expansion increased in WT rats of both sexes following 10 wks of HFD treatment, yet females exhibited greater increases in fat pad weight and adipose tissue expansion vs. males. To determine whether T cells contributes to sex differences in BP elevation in Dahl rats fed HFD, we utilized Dahl rats lacking CD247 which encodes the T cell receptor CD3 chain that is required for T cell signaling. 10 wks of HF feeding did not change BP in either sex of Dahl CD247 KO rats. There were attenuated increases in fat pad weight and adipocyte expansion in Dahl CD247 KO rats and females exhibited more pronounced attenuations than males. Flow cytometric analysis revealed that HFD decreased Tregs and increased Th17 cells in both sexes of Dahl WT rats and females on HFD had the most pro-inflammatory T cell profile indicted by the Th17 cells:Tregs ratio. Our data suggest that greater adipocyte expansion with a HFD feeding in female Dahl rats vs. male might result in greater recruitment and activation of pro-inflammatory T cells and larger increases in BP.

Modulation of the p75 neurotrophin receptor using LM11A-31 prevents diabetes-induced retinal vascular permeability in mice via inhibition of inflammation and the RhoA kinase pathway

AIMS/HYPOTHESIS

Breakdown of the inner blood-retinal barrier (BRB) is an early event in the pathogenesis of diabetic macular oedema, that eventually leads to vision loss. We have previously shown that diabetes causes an imbalance of nerve growth factor (NGF) isoforms resulting in accumulation of its precursor proNGF and upregulation of the p75 neurotrophin receptor (p75^NTR), with consequent increases in the activation of Ras homologue gene family, member A (RhoA). We also showed that genetic deletion of p75^NTR in diabetes preserved the BRB and prevented inflammatory mediators in retinas. This study aims to examine the therapeutic potential of LM11A-31, a small-molecule p75^NTR modulator and proNGF antagonist, in preventing diabetes-induced BRB breakdown. The study also examined the role of p75^NTR/RhoA downstream signalling in mediating cell permeability.

METHODS

Male C57BL/6 J mice were rendered diabetic using streptozotocin injection. After 2 weeks of diabetes, mice received oral gavage of LM11A-31 (50 mg kg^-1 day^-1) or saline (NaCl 154 mmol/l) for an additional 4 weeks. BRB breakdown was assessed by extravasation of BSA-AlexaFluor-488. Direct effects of proNGF were examined in human retinal endothelial (HRE) cells in the presence or absence of LM11A-31 or the Rho kinase inhibitor Y-27632.

RESULTS

Diabetes triggered BRB breakdown and caused significant increases in circulatory and retinal TNF-α and IL-1β levels. These effects coincided with significant decreases in retinal NGF and increases in vascular endothelial growth factor and proNGF expression, as well as activation of RhoA. Interventional modulation of p75^NTR activity through treatment of mouse models of diabetes with LM11A-31 significantly mitigated proNGF accumulation and preserved BRB integrity. In HRE cells, treatment with mutant proNGF (10 ng/ml) triggered increased cell permeability with marked reduction of expression of tight junction proteins, zona occludens-1 (ZO-1) and claudin-5, compared with control, independent of inflammatory mediators or cell death. Modulating p75^NTR significantly inhibited proNGF-mediated RhoA activation, occludin phosphorylation (at serine 490) and cell permeability. ProNGF induced redistribution of ZO-1 in the cell wall and formation of F-actin stress fibres; these effects were mitigated by LM11A-31.

CONCLUSIONS/INTERPRETATION

Targeting p75^NTR signalling using LM11A-31, an orally bioavailable receptor modulator, may offer an effective, safe and non-invasive therapeutic strategy for treating macular oedema, a major cause of blindness in diabetes.

Deletion of the Neurotrophin Receptor p75NTR Prevents Diabetes-Induced Retinal Acellular Capillaries in Streptozotocin-Induced Mouse Diabetic Model

Diabetic retinopathy is characterized by early stage of retinal neuro-inflammation that triggers development of acellular capillaries and a late stage of pathological neovascularization. Due to limited treatment options, there is a pressing need to develop new therapeutics. Our group discovered that diabetes-impaired processing of the nerve growth factor precursor (proNGF) resulting in its accumulation and its receptor p75^NTR. Here, we examine the protective effects of modulating p75^NTR in experimental model of diabetic retinopathy. Diabetes was induced using streptozotocin in both wild type (WT) and p75^NTR knockout (p75KO) mice. Retinal inflammation and microvascular dysfunction were assessed. Western blot analysis was performed to assess expression of apoptotic and inflammatory markers and levels of the neurotrophin, p75^NTR and ephrin-B2. Deletion of p75^NTR did not alter body weight or diabetes status compared to WT mice. In WT-mice, diabetes triggered retinal inflammation, significant decrease in pericyte count and marked increase in development of occluded (acellular) capillary formation after 24-weeks. Deletion of p75^NTR prevented acellular capillary, restored pericyte count, and inhibited the retinal Ephrin-B2, activation of the stress-kinase JNK and apoptotic marker cleaved caspase-3 in the diabetic retina. Deletion of p75^NTR reduced retinal inflammation, and proNGF expression. These effects coincided with increased NGF level and TrkA activation in the diabetic retina. Targeting p75^NTR using genetic approach protected the retina from the impact of long-term diabetes in mediating microvascular degeneration and maintains the balance of NGF/proNGF level. Together, these results provide rationale that targeting p75^NTR may offer novel and effective therapeutic strategy to combat diabetic retinopathy.

Netrin-1 is a novel regulator of vascular endothelial function in diabetes

BACKGROUND

Netrin-1, a secreted laminin-like protein identified as an axon guidance molecule, has been shown to be of critical importance in the cardiovascular system. Recent studies have revealed pro-angiogenic, anti-apoptotic and anti-inflammatory properties of netrin-1 as well as cardioprotective actions against myocardial injury in diabetic mice.

AIM

To examine the role of netrin-1 in diabetes-and high glucose (HG)-induced vascular endothelial dysfunction (VED) using netrin-1 transgenic mice (Tg3) and cultured bovine aortic endothelial cells (BAEC).

MAIN OUTCOME

Overexpression of netrin-1 prevented diabetes-induced VED in aorta from diabetic mice and netrin-1 treatment attenuated HG-induced impairment of nitric oxide synthase (NOS) function in BAECs.

METHODS AND RESULTS

Experiments were performed in Tg3 and littermate control (WT) mice rendered diabetic with streptozotocin (STZ) and in BAECs treated with HG (25 mmol/L). Levels of netrin-1 and its receptor DCC, markers of inflammation and apoptosis and vascular function were assessed in aortas from diabetic and non-diabetic Tg3 and WT mice. Vascular netrin-1 in WT mice was reduced under diabetic conditions. Aortas from non-diabetic Tg3 and WT mice showed similar maximum endothelium-dependent relaxation (MEDR) (83% and 87%, respectively). MEDR was markedly impaired in aorta from diabetic WT mice (51%). This effect was significantly blunted in Tg3 diabetic aortas (70%). Improved vascular relaxation in Tg3 diabetic mice was associated with increased levels of phospho-ERK1/2 and reduced levels of oxidant stress, NFκB, COX-2, p16INK4A, cleaved caspase-3 and p16 and p53 mRNA. Netrin-1 treatment prevented the HG-induced decrease in NO production and elevation of oxidative stress and apoptosis in BAECs.

CONCLUSIONS

Diabetes decreases aortic levels of netrin-1. However, overexpression of netrin-1 attenuates diabetes-induced VED and limits the reduction of NO levels, while increasing expression of p-ERK1/2, and suppressing oxidative stress and inflammatory and apoptotic processes. Enhancement of netrin-1 function may be a useful therapeutic means for preventing vascular dysfunction in diabetes.

Historical epidemiology of hepatitis C virus in select countries-volume 4

Due to the introduction of newer, more efficacious treatment options, there is a pressing need for policy makers and public health officials to develop or adapt national hepatitis C virus (HCV) control strategies to the changing epidemiological landscape. To do so, detailed, country-specific data are needed to characterize the burden of chronic HCV infection. In this study of 17 countries, a literature review of published and unpublished data on HCV prevalence, viraemia, genotype, age and gender distribution, liver transplants and diagnosis and treatment rates was conducted, and inputs were validated by expert consensus in each country. Viraemic prevalence in this study ranged from 0.2% in Hong Kong to 2.4% in Taiwan, while the largest viraemic populations were in Nigeria (2 597 000 cases) and Taiwan (569 000 cases). Diagnosis, treatment and liver transplant rates varied widely across the countries included in this analysis, as did the availability of reliable data. Addressing data gaps will be critical for the development of future strategies to manage and minimize the disease burden of hepatitis C.

The present and future disease burden of hepatitis C virus infections with today's treatment paradigm: Volume 4

Factors influencing the morbidity and mortality associated with viremic hepatitis C virus (HCV) infection change over time and place, making it difficult to compare reported estimates. Models were developed for 17 countries (Bahrain, Bulgaria, Cameroon, Colombia, Croatia, Dominican Republic, Ethiopia, Ghana, Hong Kong, Jordan, Kazakhstan, Malaysia, Morocco, Nigeria, Qatar and Taiwan) to quantify and characterize the viremic population as well as forecast the changes in the infected population and the corresponding disease burden from 2015 to 2030. Model inputs were agreed upon through expert consensus, and a standardized methodology was followed to allow for comparison across countries. The viremic prevalence is expected to remain constant or decline in all but four countries (Ethiopia, Ghana, Jordan and Oman); however, HCV-related morbidity and mortality will increase in all countries except Qatar and Taiwan. In Qatar, the high-treatment rate will contribute to a reduction in total cases and HCV-related morbidity by 2030. In the remaining countries, however, the current treatment paradigm will be insufficient to achieve large reductions in HCV-related morbidity and mortality.

Strategies to manage hepatitis C virus infection disease burden-Volume 4

The hepatitis C virus (HCV) epidemic was forecasted through 2030 for 17 countries in Africa, Asia, Europe, Latin America and the Middle East, and interventions for achieving the Global Health Sector Strategy on viral hepatitis targets-"WHO Targets" (65% reduction in HCV-related deaths, 90% reduction in new infections and 90% of infections diagnosed by 2030) were considered. Scaling up treatment and diagnosis rates over time would be required to achieve these targets in all but one country, even with the introduction of high SVR therapies. The scenarios developed to achieve the WHO Targets in all countries studied assumed the implementation of national policies to prevent new infections and to diagnose current infections through screening.

Hyperhomocysteinemia Alters Retinal Endothelial Cells Barrier Function and Angiogenic Potential via Activation of Oxidative Stress

Hyperhomocysteinemia (HHcy) is associated with several human visual disorders, such as diabetic retinopathy (DR) and age-related macular degeneration (AMD). Breakdown of the blood-retinal barrier (BRB) is linked to vision loss in DR and AMD. Our previous work revealed that HHcy altered BRB in retinal endothelial cells in vivo. Here we hypothesize that homocysteine (Hcy) alters retinal endothelial cell barrier function and angiogenic potential via activation of oxidative stress. Human retinal endothelial cells (HRECs) treated with and without different concentrations of Hcy showed a reduction of tight junction protein expression, increased FITC dextran leakage, decreased transcellular electrical resistance and increased angiogenic potential. In addition, HRECs treated with Hcy showed increased production of reactive oxygen species (ROS). The anti-oxidant N-acetyl-cysteine (NAC) reduced ROS formation and decreased FITC-dextran leakage in Hcy treated HRECs. A mouse model of HHcy, in which cystathionine-β-synthase is deficient (cbs^−/−), was evaluated for oxidative stress by dichlolorofluorescein (DCF), dihydroethidium (DHE) staining. There was a marked increase in ROS production and augmented GSH reductase and antioxidant regulator NRF2 activity, but decreased antioxidant gene expression in retinas of hyperhomocysteinemic mice. Our results suggest activation of oxidative stress as a possible mechanism of HHcy induced retinal endothelial cell dysfunction.

Honey feeding protects kidney against cisplatin nephrotoxicity through suppression of inflammation

Cisplatin is a highly effective chemotherapeutic drug used to treat a wide variety of solid tumors. However, its use was limited due its dose-limiting toxicity to the kidney. Currently, there are no therapies available to treat or prevent cisplatin nephrotoxicity. Honey is a naturally occurring complex liquid and widely used in traditional Ayurvedic medicine to treat many illnesses. However, its effect on cisplatin nephrotoxicity is unknown. To determine the role of honey in cisplatin nephrotoxicity, animals were pretreated orally for a week and then cisplatin was administered. Honey feeding was continued for another 3 days. Our results show that animals with cisplatin-induced kidney dysfunction, as determined by increased serum creatinine, which received honey feeding had less kidney dysfunction. Improved kidney function was associated with better preservation of kidney morphology in honey-treated group as compared to the cisplatin alone-treated group. Interestingly, honey feeding significantly reduced cisplatin-induced tubular epithelial cell death, immune infiltration into the kidney as well as cytokine and chemokine expression and excretion as compared to cisplatin treated animals. Western blot analysis shows that cisplatin-induced increase in phosphorylation of NFkB was completely suppressed with honey feeding. In conclusion, honey feeding protects the kidney against cisplatin nephrotoxicity through suppression of inflammation and NFkB activation.

Asian-Pacific clinical practice guidelines on the management of hepatitis B: a 2015 update

Worldwide, some 240 million people have chronic hepatitis B virus (HBV), with the highest rates of infection in Africa and Asia. Our understanding of the natural history of HBV infection and the potential for therapy of the resultant disease is continuously improving. New data have become available since the previous APASL guidelines for management of HBV infection were published in 2012. The objective of this manuscript is to update the recommendations for the optimal management of chronic HBV infection. The 2015 guidelines were developed by a panel of Asian experts chosen by the APASL. The clinical practice guidelines are based on evidence from existing publications or, if evidence was unavailable, on the experts' personal experience and opinion after deliberations. Manuscripts and abstracts of important meetings published through January 2015 have been evaluated. This guideline covers the full spectrum of care of patients infected with hepatitis B, including new terminology, natural history, screening, vaccination, counseling, diagnosis, assessment of the stage of liver disease, the indications, timing, choice and duration of single or combination of antiviral drugs, screening for HCC, management in special situations like childhood, pregnancy, coinfections, renal impairment and pre- and post-liver transplant, and policy guidelines. However, areas of uncertainty still exist, and clinicians, patients, and public health authorities must therefore continue to make choices on the basis of the evolving evidence. The final clinical practice guidelines and recommendations are presented here, along with the relevant background information.