Mortality, Hospitalization, and Quality of Life among Patients with Hepatitis C Infection on Hemodialysis

BACKGROUND AND OBJECTIVES

Hepatitis C virus (HCV) infection is widely prevalent among patients on hemodialysis (HD), but very rarely treated. The aim of our study is to evaluate the burdens of HCV suffered by patients on HD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Dialysis Outcomes and Practice Patterns Study is an international, prospective, cohort study of patients on HD. We reviewed the HCV status of 76,689 adults enrolled between 1996 and 2015. We compared HCV-positive (HCV+) with HCV-negative (HCV-) patients for risk of mortality, hospitalization, decline in hemoglobin concentration <8.5 g/dl, and red blood cell transfusion. We also compared health-related quality of life scores using the Kidney Disease Quality of Life instrument and the Center for Epidemiologic Studies Short Depression Scale. We adjusted for age, sex, race, years on dialysis, 14 comorbid conditions (including hepatitis B infection), and serum albumin, phosphorus, and creatinine concentrations.

RESULTS

A total of 7.5% of patients were HCV+ at enrollment. Serum concentrations of alanine aminotransferase and aspartate aminotransferase were not markedly elevated in HCV+ patients on HD; the mean concentrations were only 22.6 and 21.8 U/L, respectively. Median follow-up was 1.4 years. Case-mix adjusted hazard ratios (95% confidence intervals) for HCV+ versus HCV- patients were 1.12 (1.05 to 1.20) for all-cause mortality, 5.90 (3.67 to 9.50) for hepatic-related mortality, 1.09 (1.04 to 1.13) for all-cause hospitalization, and 4.40 (3.14 to 6.15) for hepatic-related hospitalization. Quality of life measures indicated significantly worse scores for physical function, pain, vitality, mental health, depression, pruritus, and anorexia among HCV+ patients. The adjusted hazard ratio for transfusion was 1.36 (95% CI, 1.20 to 1.55) and incidence of hemoglobin concentration <8.5 g/dl was 1.12 (95% CI, 1.03 to 1.21). Only 1.5% of HCV+ patients received antiviral medication.

CONCLUSIONS

HCV infection among patients on HD is associated with higher risk of death, hospitalization, and anemic complications, and worse quality of life scores. Internationally, HCV infection is almost never treated in patients on HD. Our data provide a rationale for more frequent treatment of HCV in this population.

Effect of Sofosbuvir-Based Hepatitis C Virus Therapy on Kidney Function in Patients with CKD

BACKGROUND AND OBJECTIVES

Hepatitis C virus infection is common in patients with CKD and leads to accelerated progression to ESRD. Sofosbuvir is a potent direct-acting antiviral therapy against hepatitis C virus; however, there are concerns about its safety in patients with CKD. The objective of our study was to determine the safety and efficacy of sofosbuvir in patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied a retrospective observational cohort of patients with CKD defined by eGFR<60 ml/min per 1.73 m2, ≥30 mg albuminuria per 1 g creatinine, or ≥200 mg proteinuria per 1 g creatinine who received sofosbuvir-based therapy in a large health care system. Regression models were constructed to predict likelihood of sustained virologic response, detect adverse events, and examine changes in eGFR from baseline to follow-up.

RESULTS

Ninety-eight patients with CKD (42% stage 1 or 2 CKD and 58% stage 3 CKD) were included. Mean age was 62 years old, 78% were men, and 65% were white. Additionally, 49% of patients had diabetes, 38% of patients had cirrhosis, and 33% of patients had prior solid organ transplant. Overall sustained virologic response was 81% and varied by regimen used and viral genotype. Average baseline eGFR was equivalent to average on-treatment eGFR, but seven patients experienced a rise in creatinine ≥1.5 times baseline while taking sofosbuvir; all but one recovered. In patients with eGFR<60 ml/min per 1.73 m2 at baseline (stage 3 CKD), regression models showed that hepatitis C cure was associated with a 9.3 (95% confidence interval, 0.44 to 18) ml/min per 1.73 m2 improvement in eGFR during the 6-month post-treatment follow-up period. Adverse events were common (81%), but serious adverse events (17%) and treatment discontinuations (8%) were uncommon.

CONCLUSIONS

Sofosbuvir-based direct-acting antiviral therapy is safe and effective in a cohort of patients with CKD infected with hepatitis C.

Viral-Associated GN: Hepatitis B and Other Viral Infections

By definition, viral-associated GN indicates the direct pathogenic relationship between active viral replication and the development of acute GN. This definition is in sharp contrast to the semantic label and pathophysiologic foundation behind postinfectious GN that uniquely develops only during a period of resolved and absent active infection. The primary example of postinfectious GN are the glomerular lesions described after a pharyngeal or cutaneous streptococcal infection and do not represent the clinical or immunologic pattern seen with viral-associated GN. Hepatitis B (HBV) is the most common chronic viral infection in the world affecting >400 million people which is more than double the prevalence of chronic HIV and hepatitis C carriers combined. In addition, 10%-20% of HBV patients may be coinfected with hepatitis C and 5%-10% will have coinfection with HIV. Being able to distinguish the different types of GN seen with each viral infection is essential for the practicing clinician as each virus requires its own specific antiviral therapy. HBV-induced immune complex disease with renal injury lies on one end of the spectrum of disorders that occurs after a prolonged chronic carrier state. On the opposite end of the spectrum are renal diseases that develop from acute or subacute viral infections. One important glomerular lesion in this category is the association of collapsing FSGS with acute active cytomegalovirus, Epstein-Barr virus, and parvovirus B19 infection. The data supporting or disproving this relationship for each of these viruses will be discussed. A second renal manifestation of acute viral infections often occurs with many different sporadic or epidemic infections such as dengue and hantavirus and can lead to a transient proliferative GN that resolves upon viral clearance. The complex interplay of HBV and all viruses with the immune system provides conceptual lessons on the pathophysiology of immune complex GN that can be applied to all infection-related renal disease and plays an integral role in developing an approach to therapeutic intervention.

Structural requirements for the antiviral activity of the human MxA protein against Thogoto and influenza A virus

The interferon-induced dynamin-like MxA protein has broad antiviral activity against many viruses, including orthomyxoviruses such as influenza A and Thogoto virus and bunyaviruses such as La Crosse virus. MxA consists of an N-terminal globular GTPase domain, a connecting bundle signaling element, and the C-terminal stalk that mediates oligomerization and antiviral specificity. We previously reported that the disordered loop L4 that protrudes from the compact stalk is a key determinant of antiviral specificity against influenza A and Thogoto virus. However, the role of individual amino acids for viral target recognition remained largely undefined. By mutational analyses, we identified two regions in the C-terminal part of L4 that contribute to an antiviral interface. Mutations in the proximal motif, at positions 561 and 562, abolished antiviral activity against orthomyxoviruses but not bunyaviruses. In contrast, mutations in the distal motif, around position 577, abolished antiviral activity against both viruses. These results indicate that at least two structural elements in L4 are responsible for antiviral activity and that the proximal motif determines specificity for orthomyxoviruses, whereas the distal sequence serves a conserved structural function.

Serum Level of Antibodies Against Hepatitis B Core Protein Is Associated With Clinical Relapse After Discontinuation of Nucleos(t)ide Analogue Therapy

BACKGROUND & AIMS

Levels of antibodies against the hepatitis B virus (HBV) core protein (anti-HBc) have been associated with response to nucleos(t)ide analogue and (peg)interferon therapy in patients with chronic HBV infection. We performed a prospective study to determine whether the total serum level of anti-HBc level (immunoglobulins M and G) is associated with clinical relapse after discontinuation of nucleos(t)ide analogue-based therapy.

METHODS

We collected data from patients with chronic HBV infection who discontinued nucleos(t)ide analogue therapy according to pre-specified stopping criteria, recruited from November 2012 through July 2016 at an academic hospital in Guangzhou, China. Patients were followed through February 2017. We performed comprehensive biochemical and virologic tests at every visit, and anti-HBc was quantified for 2 years after treatment cessation (at baseline and weeks 4, 8, 12, 24, 48, and 96). The primary endpoint was clinical relapse, defined as level of HBV DNA >2000 IU/mL and level of alanine aminotransferase more than 2-fold the upper limit of normal-these were also the criteria for retreatment.

RESULTS

We followed 100 patients (71% positive for HB e antigen [HBeAg] at the start of nucleos(t)ide analogue therapy, 43% treated with entecavir or tenofovir) for a median of 2.5 years after stopping therapy. Clinical relapse occurred in 39 patients (in 46% of patients at year 4 after discontinuation). High level of anti-HBc at the end of treatment (hazard ratio [HR], 0.31 per log IU/mL; P = .002) and low level of HB surface antigen (HBsAg) at the end of treatment (HR, 1.71 per log IU/mL; P = .032) were associated with a reduced risk of clinical relapse after adjusting for age, start of nucleos(t)ide analogue therapy, HBeAg-status, and consolidation therapy duration. At year 4, 21% of patients with anti-HBc levels at the end of treatment ≥1000 IU/mL developed a clinical relapse compared to 85% of patients with levels <100 IU/mL (P < .001). An HBsAg level at the end of treatment ≤100 IU/mL was associated with a reduced risk of relapse (HR 0.30; P = .045). However, 82% of patients had levels of HBsAg above 100 IU/mL; for these patients, level of anti-HBc at the end of treatment could be used to determine the risk of relapse (HR 0.39 per log IU/mL; P = .005).

CONCLUSION

In a median 2.5-year follow-up study of patients with chronic HBV infection who stopped nucleos(t)ide analogue therapy, total serum level of anti-HBc at the end of treatment was associated with risk of clinical relapse. Serum level of anti-HBc might be used to select patients suitable for discontinuing nucleos(t)ide analogue therapy.

Negative regulation of interferon-induced transmembrane protein 3 by SET7-mediated lysine monomethylation

Although lysine methylation is classically known to regulate histone function, its role in modulating antiviral restriction factor activity remains uncharacterized. Interferon-induced transmembrane protein 3 (IFITM3) was found monomethylated on its lysine 88 residue (IFITM3-K88me1) to reduce its antiviral activity, mediated by the lysine methyltransferase SET7. Vesicular stomatitis virus and influenza A virus infection increased IFITM3-K88me1 levels by promoting the interaction between IFITM3 and SET7, suggesting that this pathway could be hijacked to support infection; conversely, IFN-α reduced IFITM3-K88me1 levels. These findings may have important implications in the design of therapeutics targeting protein methylation against infectious diseases.

Zoster sine herpete: a review

Zoster sine herpete (ZSH) is one of the atypical clinical manifestations of herpes zoster (HZ), which stems from infection and reactivation of the varicella-zoster virus (VZV) in the cranial nerve, spinal nerve, viscera, or autonomic nerve. Patients with ZSH display variable symptoms, such as neuralgia, however, different from HZ, ZSH show no zoster, which makes clinical diagnosis difficult. ZSH not only causes initial symptoms, such as neuropathic pain in the affected nerve, Bell palsy, and Ramsay Hunt syndrome, but also postherpetic neuralgia and fatal complications such as VZV encephalitis and stroke. The misdiagnosis of ZSH and tardy antiviral treatment may lead to severe ZSH sequelae. We review the publications related to ZSH, especially its diagnosis with VZV DNA and/or anti-VZV immunoglobulin (IgG and IgM). More work about ZSH, especially ZSH epidemiological survey and guidelines for its diagnosis and treatment, are needed because most of the present studies are case reports.

Hepatitis C Virus Treatment: Is It Possible To Cure All Hepatitis C Virus Patients?

The recent advances in hepatitis C virus (HCV) therapeutics have brought combinations of direct acting antiviral medications that offer interferon-free, well-tolerated regimens with sustained virologic response rates greater than 90% in clinical trials for many patient groups. The successes have prompted discussions regarding cure for all patients. These regimens have already demonstrated the ability to cure previously challenging patient groups, including human immunodeficiency virus-HCV coinfection, decompensated cirrhosis, and post-liver transplantation. Limitations exist in the current portfolio of agents, with suboptimal outcomes for genotype 3 and limited data in genotypes 5 and 6. More data are urgently needed in patients with chronic kidney disease and in children. With ongoing developments, highly effective regimens for all these patient groups are within reach. To deliver HCV treatment throughout the world and particularly in low- and middle-income countries, regimens need to be affordable but also pan-genotypic, well-tolerated, and delivered once daily for 4-8 weeks. With such a regimen, cure for all patients would then hinge on the ability to identify patients with HCV infection and deliver treatment within their communities. This review will discuss the strategies that will be necessary to realize this opportunity to cure all persons with HCV infection.

Viral-Associated GN: Hepatitis C and HIV

Viruses are capable of inducing a wide spectrum of glomerular disorders that can be categorized on the basis of the duration of active viremia: acute, subacute, or chronic. The variable responses of the adaptive immune system to each time period of viral infection results mechanistically in different histologic forms of glomerular injury. The unique presence of a chronic viremic carrier state with either hepatitis C (HCV) or HIV has led to the opportunity to study in detail various pathogenic mechanisms of viral-induced glomerular injury, including direct viral infection of renal tissue and the development of circulating immune complexes composed of viral antigens that deposit along the glomerular basement membrane. Epidemiologic data show that approximately 25%-30% of all HIV patients are coinfected with HCV and 5%-10% of all HCV patients are coinfected with HIV. This situation can often lead to a challenging differential diagnosis when glomerular disease occurs in this dual-infected population and requires the clinician to be familiar with the clinical presentation, laboratory workup, and pathophysiology behind the development of renal disease for both HCV and HIV. Both of these viruses can be categorized under the new classification of infection-associated GN as opposed to being listed as causes of postinfectious GN as has previously been applied to them. Neither of these viruses lead to renal injury after a latent period of controlled and inactive viremia. The geneses of HCV- and HIV-associated glomerular diseases share a total dependence on the presence of active viral replication to sustain renal injury so the renal disease cannot be listed under "postinfectious" GN. With the new availability of direct-acting antivirals for HCV and more effective combined antiretroviral therapy for HIV, successful remission and even regression of glomerular lesions can be achieved if initiated at an early stage.

A French Cohort Study of Kidney Retransplantation after Post-Transplant Lymphoproliferative Disorders

BACKGROUND AND OBJECTIVES

Post-transplant lymphoproliferative disorders arising after kidney transplantation portend an increased risk of morbidity and mortality. Retransplantation of patients who had developed post-transplant lymphoproliferative disorder remains questionable owing to the potential risks of recurrence when immunosuppression is reintroduced. Here, we investigated the feasibility of kidney retransplantation after the development of post-transplant lymphoproliferative disorder.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We reviewed the data from all patients who underwent kidney retransplantation after post-transplant lymphoproliferative disorder in all adult kidney transplantation centers in France between 1998 and 2015.

RESULTS

We identified a total of 52 patients with kidney transplants who underwent 55 retransplantations after post-transplant lymphoproliferative disorder. The delay from post-transplant lymphoproliferative disorder to retransplantation was 100±44 months (28-224); 98% of patients were Epstein-Barr virus seropositive at the time of retransplantation. Induction therapy for retransplantation was used in 48 patients (i.e., 17 [31%] patients received thymoglobulin, and 31 [57%] patients received IL-2 receptor antagonists). Six patients were also treated with rituximab, and 53% of the patients received an antiviral drug. The association of calcineurin inhibitors, mycophenolate mofetil, and steroids was the most common maintenance immunosuppression regimen. Nine patients were switched from a calcineurin inhibitor to a mammalian target of rapamycin inhibitor. One patient developed post-transplant lymphoproliferative disorder recurrence at 24 months after retransplantation, whereas post-transplant lymphoproliferative disorder did not recur in 51 patients.

CONCLUSIONS

The recurrence of post-transplant lymphoproliferative disorder among patients who underwent retransplantation in France is a rare event.

Expression and regulatory effects of murine Schlafen (Slfn) genes in malignant melanoma and renal cell carcinoma

There is emerging evidence that the IFN-inducible family of Slfn genes and proteins play important roles in cell cycle progression and control of cellular proliferation, but the precise functional roles of different Slfn members in the regulation of tumorigenesis remain unclear. In the present study, we undertook a systematic analysis on the expression and functional relevance of different mouse Slfn genes in malignant melanoma and renal cell carcinoma cells. Our studies demonstrate that several mouse Slfn genes are up-regulated in response to IFN treatment of mouse melanoma and renal cell carcinoma cells, including Slfn1, Slfn2, Slfn4, Slfn5, and Slfn8. Our data show that Slfn2 and Slfn3 play essential roles in the control of mouse malignant melanoma cell proliferation and/or anchorage-independent growth, suggesting key and non-overlapping roles for these genes in the control of malignant melanoma tumorigenesis. In renal cell carcinoma cells, in addition to Slfn2 and Slfn3, Slfn5 also exhibits important antineoplastic effects. Altogether, our findings indicate important functions for distinct mouse Slfn genes in the control of tumorigenesis and provide evidence for differential involvement of distinct members of this gene family in controlling tumorigenesis. They also raise the potential of future therapeutic approaches involving modulation of expression of members of this family of genes in malignant melanoma and renal cell carcinoma.

The Effect of Aqueous Extract of Glycyrrhiza glabra on Herpes Simplex Virus 1

BACKGROUND

Herpes Simplex Virus 1 (HSV-1) resistance to drugs and the side effects of drugs have drawn the attention of investigators to herbal plants.

OBJECTIVES

The main aim of the current research was to investigate the effects of Glycyrrhiza glabra (liquorice root) on HSV-1. One of the objectives of the current research was to determine the efficacy and the effect of the elapsed incubation time of treating the Vero cells infected with HSV-1 by G. glabra. In addition, the effect of cells pretreatment with licorice root extract, preincubation of virus with licorice root extract, and the antiviral activity were assessed.

PATIENTS AND METHODS

Vero cells were incubated after adding different concentrations of aqueous extracts of G. glabra. The cells were incubated during various time courses. Cytotoxicity assay, determining the 50% tissue culture infectious dose (TCID50), and incubation of HSV-1 with licorice root extract prior to viral infection were performed.

RESULTS

Internal association among different experiment groups showed the significant difference in the efficacy of the extract with regard to incubation period between one and four hours, one and eight hours, four and 12 hours, and eight and 12 hours. Moreover, there was a significant difference with regard to efficacy among the pretreatment of cells with extract for two hours, incubation of virus with extract for one hour, incubation of virus with extract for two hours.

CONCLUSIONS

G. glabra showed the characteristics of a novel antiviral medication; however, more in vitro experiments are needed to determine the antiherpetic activities of the G. glabra.

Gastroschisis in Europe - A Case-malformed-Control Study of Medication and Maternal Illness during Pregnancy as Risk Factors

BACKGROUND

Gastroschisis, a congenital anomaly of the abdomen, is associated with young maternal age and has increased in prevalence in many countries. Maternal illness and medication exposure are among environmental risk factors implicated in its aetiology.

METHODS

A population-based case-malformed control study was conducted using data from 18 European congenital anomaly registries, with information on first trimester medication use, covering 8 million births 1995-2012. 1577 gastroschisis cases (of which 4% stillbirths, 11% terminations of pregnancy) were compared to 153 357 non-chromosomal/monogenic controls. Literature review identified previous associations concerning maternal illness and medication exposure to be tested as signals. Logistic regression adjusted for maternal age group, registry, and time period was used to evaluate associations.

RESULTS

Comparing gastroschisis to other congenital anomalies, the data supported signals concerning maternal depression (aOR 2.52, 95% CI 1.45, 4.39), antidepressant use (aOR 2.03, 95% CI 1.22, 3.38), postnatal depression/psychosis following a previous pregnancy (aOR 8.32, 95% CI 2.56, 27.01), sexually transmitted infections (aOR 2.85, 95% CI 1.13, 7.24), topical antivirals (aOR 5.31, 95% CI 1.63, 17.33), and continuation of oral contraceptives in early pregnancy (aOR 2.17, 95% CI 1.13, 4.18). Exploratory analyses suggested associations with a wider range of maternal infections and medications, including tonsillitis and the expectorant bromhexine.

CONCLUSIONS

While it is difficult to disentangle the effects of the medication and underlying indication, our results add to the evidence base on preventable risk factors for gastroschisis. These risk factors may contribute to the higher risk among young mothers, and geographical and temporal variation in prevalence.

Non-Immunosuppressive Cyclophilin Inhibitors

Cyclophilins, enzymes with peptidyl-prolyl cis/trans isomerase activity, are relevant to a large variety of biological processes. The most abundant member of this enzyme family, cyclophilin A, is the cellular receptor of the immunosuppressive drug cyclosporine A (CsA). As a consequence of the pathophysiological role of cyclophilins, particularly in viral infections, there is a broad interest in cyclophilin inhibition devoid of immunosuppressive activity. This Review first gives an introduction into the physiological and pathophysiological roles of cyclophilins. The presentation of non-immunosuppressive cyclophilin inhibitors will commence with drugs based on chemical modifications of CsA. The naturally occurring macrocyclic sanglifehrins have become other lead structures for cyclophilin-inhibiting drugs. Finally, de novo designed compounds, whose structures are not derived from or inspired by natural products, will be presented. Relevant synthetic concepts will be discussed, but the focus will also be on biochemical studies, structure-activity relationships, and clinical studies.

Dynamics of hepatitis C virus (HCV) RNA-dependent RNA polymerase NS5B in complex with RNA

The hepatitis C virus (HCV) non-structural protein 5B (NS5B) is an RNA-dependent RNA polymerase that is essentially required for viral replication. Although previous studies revealed important properties of static NS5B-RNA complexes, the nature and relevance of dynamic interactions have yet to be elucidated. Here, we devised a single molecule Förster Resonance Energy Transfer (SM-FRET) assay to monitor temporal changes upon binding of NS5B to surface immobilized RNA templates. The data show enzyme association-dissociation events that occur within the time resolution of our setup as well as FRET-fluctuations in association with stable binary complexes that extend over prolonged periods of time. Fluctuations are shown to be dependent on the length of the RNA substrate, and enzyme concentration. Mutations in close proximity to the template entrance (K98E, K100E), and in the center of the RNA binding channel (R394E), reduce both the population of RNA-bound enzyme and the fluctuations associated to the binary complex. Similar observations are reported with an allosteric nonnucleoside NS5B inhibitor. Our assay enables for the first time the visualization of association-dissociation events of HCV-NS5B with RNA, and also the direct monitoring of the interaction between HCV NS5B, its RNA template, and finger loop inhibitors. We observe both a remarkably low dissociation rate for wild type HCV NS5B, and a highly dynamic enzyme-RNA binary complex. These results provide a plausible mechanism for formation of a productive binary NS5B-RNA complex, here NS5B slides along the RNA template facilitating positioning of its 3' terminus at the enzyme active site.

Hepatitis B and its Relationship With Oxidative Stress

CONTEXT

Despite the great breakthroughs we have witnessed in the last 50 years in the prevention, diagnosis, and treatment of hepatitis B, we are still far from eradicating or even curing the disease. Achieving further progress in controlling this disease will not be possible without discovering the exact pathogenesis behind it. One prime suspect in the pathogenesis of various diseases is oxidative stress. This review will exclusively explore hepatitis B in the context of oxidative stress to obtain a more comprehensive clinical perspective on its pathogenesis and eventual medical therapy.

EVIDENCE ACQUISITION

We systematically searched PubMed, Google Scholar, Web of Science, EMBASE, and Scopus using an extensive list of keywords in the following three categories: 1) Hepatitis B and oxidation 2) Hepatitis B and antioxidant system 3) Effects of approved anti-hepatitis B drugs on redox status. All relevant articles were obtained and reviewed carefully after the exclusion criteria were deployed.

RESULTS

There is great evidence indicating extensive oxidative stress occurs in hepatitis B. This oxidative stress takes place on multiple levels, including lipid peroxidation, DNA oxidation, protein oxidation, and reactive oxygen and nitrogen species production. However, there are also conflicting results with regard to antioxidant therapy and antioxidant status in hepatitis B, some of which may be explained by the concept of "compensatory gaps." Nevertheless, further studies are indicated to reach a more thorough judgment.

CONCLUSIONS

Despite the presence of vast oxidative stress in hepatitis B, antioxidant therapy is not always effective as a treatment strategy, especially considering that antioxidants can act as "double-edged swords" or antioxidants; if not used at the right time or place or in the right combination, these substances can easily become pro-oxidants. Therefore, several studies will be needed to determine suitable antioxidant therapies. We propose the "2-step Combined Antioxidant Adjuvant Therapy for hepatitis B (2CAAT Hep B)" as a new strategy for antioxidant adjuvant therapy. We also suggest developing an international platform and database for antioxidant adjuvant therapy in hepatitis B (IPAATH and IDAATH) to canalize this field of research in a standardized direction, especially when complexity is a problem.

Critical roles for Rictor/Sin1 complexes in interferon-dependent gene transcription and generation of antiproliferative responses

We provide evidence that type I IFN-induced STAT activation is diminished in cells with targeted disruption of the Rictor gene, whose protein product is a key element of mTOR complex 2. Our studies show that transient or stable knockdown of Rictor or Sin1 results in defects in activation of elements of the STAT pathway and reduced STAT-DNA binding complexes. This leads to decreased expression of several IFN-inducible genes that mediate important biological functions. Our studies also demonstrate that Rictor and Sin1 play essential roles in the generation of the suppressive effects of IFNα on malignant erythroid precursors from patients with myeloproliferative neoplasms. Altogether, these findings provide evidence for critical functions for Rictor/Sin1 complexes in type I IFN signaling and the generation of type I IFN antineoplastic responses.

In Vitro Reconstitution of Metabolic Pathways: Insights into Nature's Chemical Logic

In vitro analysis of metabolic pathways is becoming a powerful method to gain a deeper understanding of Nature's core biochemical transformations. With astounding advancements in biotechnology, purification of a metabolic pathway's constitutive enzymatic components is becoming a tractable problem, and such in vitro studies allow scientists to capture the finer details of enzymatic reaction mechanisms, kinetics, and the identity of organic product molecules. In this review, we present eleven metabolic pathways that have been the subject of in vitro reconstitution studies in the literature in recent years. In addition, we have selected and analyzed subset of four case studies within these eleven examples that exemplify remarkable organic chemistry occurring within biology. These examples serves as tangible reminders that Nature's biochemical routes obey the fundamental principles of organic chemistry, and the chemical mechanisms are reminiscent of those featured in traditional synthetic organic routes. The illustrations of biosynthetic chemistry depicted in this review may inspire the development of biomimetic chemistries via abiotic chemical techniques.

Decrease of serum Angiotensin converting enzyme levels upon telbivudine treatment for chronic hepatitis B virus infection and negative correlations between the enzyme levels and estimated glumerular filtration rates

BACKGROUND

During antiviral therapy for chronic hepatitis B, renal function impairment could be a critical concern when oral nucleot(s)ide analogues were used. Paradoxically, long-term telbivudine treatment was associated with an increase of estimated glomerular filtration rate (eGFR) through unknown mechanisms.

OBJECTIVES

We aimed to investigate changes in serum protein abundances associated with renal function in response to antiviral treatments.

MATERIALS AND METHODS

Primarily, a transcriptomic assay was performed to identify differentially expressed genes in peripheral blood cells caused by the telbivudine treatment. Two genes coding angiotensin converting enzyme (ACE) and complement factor H (CFH) were screened from 14 candidate renal function-related genes. ACE and CFH production were further investigated using enzyme-linked immunoassays.

RESULTS

Verification studies showed no significant change of serum CFH levels, but there was a significant reduction of serum ACE levels by continuous telbivudine treatment for 330.00 ± 0.85 days (34 patients; paired t-test, P = 0.022). Serum HBV DNA and ALT levels also decreased (P = 0.008 and < 0.001, respectively). A significant increase in eGFR was found (33 patients, paired t-test, P = 0.002) at 708.64 ± 31.63 days. Patients' eGFRs were negatively correlated with serum ACE levels (r = -0.375, P = 0.002) but not with serum HBV DNA and ALT levels (P = 0.241 and 0.088 respectively). Significant decreases of the ACE levels were also observed upon entecavir treatment (20 patients; paired t-test, P = 0.020) at 412.88 ± 36.92 days. No significant correlation was found between serum ACE levels and eGFRs (r = -0.239, P = 0.138) in entecavir-treated patients.

CONCLUSIONS

We discovered a consistent reduction of serum ACE levels by two oral antiviral monotherapies, entecavir and telbivudine. Serum ACE levels were negatively correlated with eGFRs in telbivudine treated patients.

Essential role for the Mnk pathway in the inhibitory effects of type I interferons on myeloproliferative neoplasm (MPN) precursors

The mechanisms of generation of the antineoplastic effects of interferons (IFNs) in malignant hematopoietic cells remain to be precisely defined. We examined the activation of type I IFN-dependent signaling pathways in malignant cells transformed by Jak2V617F, a critical pathogenic mutation in myeloproliferative neoplasms (MPNs). Our studies demonstrate that during engagement of the type I IFN receptor (IFNAR), there is activation of Jak-Stat pathways and also engagement of Mnk kinases. Activation of Mnk kinases is regulated by the Mek/Erk pathway and is required for the generation of IFN-induced growth inhibitory responses, but Mnk kinase activation does not modulate IFN-regulated Jak-Stat signals. We demonstrate that for type I IFNs to exert suppressive effects in malignant hematopoietic progenitors from patients with polycythemia vera, induction of Mnk kinase activity is required, as evidenced by studies involving pharmacological inhibition of Mnk or siRNA-mediated Mnk knockdown. Altogether, these findings provide evidence for key and essential roles of the Mnk kinase pathway in the generation of the antineoplastic effects of type I IFNs in Jak2V617F-dependent MPNs.

Impact of a Rapid Point of Care Test for Influenza on Guideline Consistent Care and Antibiotic Use

BACKGROUND

Rapid influenza diagnostic tests that detect the presence of viral antigens are currently used throughout the United States but have poor sensitivity. The objective of this study was to identify if the use of a new highly accurate rapid point of care test would significantly increase the likelihood of guideline consistent care.

METHODS

We prospectively recruited 300 students at a university health clinic who presented with cough and 1 influenza-like illness symptom between December 2016 and February 2017 to receive care guided by a rapid polymerase chain reaction (PCR) test. Of the 300 patients receiving the PCR test, 264 had complete medical records and were compared to 771 who received usual care. We used a logistic regression model to identify whether PCR guided care was associated with guideline consistent care, based on the appropriate use of oseltamivir and antibiotics. We also assessed whether PCR guided care decreased the likelihood of return visits within 2 weeks by patients.

RESULTS

Logistic regression revealed that the odds of receiving guideline supported care did not significantly increase for patients who received PCR guided care (adjusted odds ratio [aOR], 1.24; 95% CI, 0.83-1.88). It significantly decreased the likelihood of an antibiotic prescription (aOR, 0.61; 95% CI, 0.40-0.94), increased the likelihood of receiving oseltamivir (aOR, 1.57; 95% CI, 1.09-2.28), and decreased the likelihood of return visit within 2 weeks (aOR, 0.19; 95% CI, 0.04-0.81).

CONCLUSIONS

The use of a rapid PCR test did not significantly improve the likelihood of guideline consistent care. However, independent of test outcome, patients who received the test were more likely to receive an antiviral and less likely to receive an antibiotic or have a return visit within 2 weeks.

Clinical efficacy of a 24-months course of lamivudine therapy in patients with HBeAg negative chronic hepatitis B: a long-term prospective study

The optimal duration of oral nucleos(t)ide analogue therapy for HBeAg negative chronic hepatitis B (CHB) has not been defined. The aim of this study was to investigate the clinical efficacy of 24-months course of lamivudine therapy in patients with HBeAg negative CHB in Korea. A total of 50 Korean patients with HBeAg negative CHB were prospectively enrolled. The patients received 100 mg/day of lamivudine orally for 24 months. Patients who showed complete response at 24 months to lamivudine therapy stopped treatment, and regular follow-up was done thereafter. The mean follow-up duration after cessation of therapy was 40.8+/-22.7 (range 12-96) months. The complete response rate at months 12 and 24 were 86.0% (43/50) and 86.0% (43/50), respectively, and the clinical breakthrough at months 12 and 24 were 4.0% (2/50) and 14.0% (7/50), respectively. The expected durability of responses at months 12, 24, and 36 after cessation of lamivudine therapy in 43 complete responders was 79.1%, 64.0%, and 56.9%, respectively. In conclusion, a 24-months course of lamivudine therapy shows high end-treatment response rate and substantial durability of initial response after cessation of therapy in HBeAg negative CHB patients in Korea.

Dynamics of Organic Anion Transporter-Mediated Tubular Secretion during Postnatal Human Kidney Development and Maturation

BACKGROUND AND OBJECTIVES

The neonatal and juvenile human kidney can be exposed to a variety of potentially toxic drugs (e.g., nonsteroidal anti-inflammatory drugs, antibiotics, antivirals, diuretics), many of which are substrates of the kidney organic anion transporters, OAT1 (SLC22A6, originally NKT) and OAT3 (SLC22A8). Despite the immense concern about the consequences of drug toxicity in this vulnerable population, the developmental regulation of OATs in the immature postnatal kidney is poorly understood.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Recognizing that today it is difficult to obtain rich data on neonatal kidney handling of OAT probes due to technical, logistic, and ethical considerations, multiple older physiologic studies that used the prototypical organic anion substrate para-aminohippurate (PAH) were reanalyzed in order to provide a quantitative description of OAT-mediated tubular secretion across the pediatric age continuum. Parametric and semiparametric models were evaluated for kidney function outcome variables of interest (maximum tubular secretory capacity of PAH [Tm_PAH], effective renal plasma flow [ERPF], and GFR).

RESULTS

Data from 119 neonates, infants, and children ranging in age from 1 day to 11.8 years were used to fit Tm_PAH, ERPF, and GFR as functions of postnatal age. Tm_PAH is low in the immediate postnatal period and increases markedly after birth, reaching 50% of the adult value (80 mg/min) at 8.3 years of age. During the first 2 years of life, Tm_PAH is lower than that of GFR when viewed as the fraction of the adult value.

CONCLUSIONS

During postnatal human kidney development, proximal tubule secretory function-as measured using PAH, a surrogate for OAT-mediated secretion of organic anion drugs, metabolites, and toxins-is low initially but increases rapidly. Despite developmental differences between species, this overall pattern is roughly consistent with animal studies. The human data raise the possibility that the acquisition of tubular secretory function may not closely parallel glomerular filtration.

Direct expression and validation of phage-selected peptide variants in mammalian cells

Phage display is a key technology for the identification and maturation of high affinity peptides, antibodies, and other proteins. However, limitations of bacterial expression restrict the range and sensitivity of assays that can be used to evaluate phage-selected variants. To address this problem, selected genes are typically transferred to mammalian expression vectors, a major rate-limiting step in the iterative improvement of peptides and proteins. Here we describe a system that combines phage display and efficient mammalian expression in a single vector, pDQ1. This system permits immediate expression of phage-selected genes as IgG1-Fc fusions in mammalian cells, facilitating the rapid, sensitive characterization of a large number of library outputs for their biochemical and functional properties. We demonstrate the utility of this system by improving the ability of a CD4-mimetic peptide to bind the HIV-1 envelope glycoprotein and neutralize HIV-1 entry. We further improved the potency of the resulting peptide, CD4mim6, by limiting its ability to induce the CD4-bound conformation of the envelope glycoprotein. Thus, CD4mim6 and its variants can be used to investigate the properties of the HIV-1 envelope glycoprotein, and pDQ1 can accelerate the discovery of new peptides and proteins through phage display.