Efficacy of Retreatment After Failed Direct-acting Antiviral Therapy in Patients With HCV Genotype 1-3 Infections

Hepatitis C virus infection is causing chronic liver disease, cirrhosis, and hepatocellular carcinoma. By combining direct-acting antivirals (DAAs), high sustained virologic response rates (SVRs) can be achieved. Resistance-associated substitutions (RASs) are commonly observed after DAA failure, and especially nonstructural protein 5A (NS5A) RASs may impact retreatment options.^1-3 Data on retreatment of DAA failure patients using first-generation DAAs are limited.^4-7 Recently, a second-generation protease- and NS5A-inhibitor plus sofosbuvir (voxilaprevir/velpatasvir/sofosbuvir [VOX/VEL/SOF]) was approved for retreatment after DAA failure.⁸ However, this and other second-generation regimens are not available in many resource-limited countries or are not reimbursed by regular insurance, and recommendations regarding the selection of retreatment regimens using first-generation DAAs are very important. This study aimed to analyze patients who were re-treated with first-generation DAAs after failure of a DAA combination therapy.

[New treatments for spinal muscular atrophy]

5‑q-associated spinal muscular atrophy (SMA) has so far been a causally untreatable disease, which leads to severe, progressive physical restrictions due to the loss of spinal motor neurons. However, the monogenetic cause of the relatively short coding "survival motor neuron" (SMN) 1 gene sequence and the presence of almost identical gene copies, the SMN2 genes, offer favorable conditions for the development of new therapeutic approaches. While previously only supportive and palliative therapies could be used, new disease-modifying drugs are now available for the first time. Nusinersen, an antisense oligonucleotide (ASO), is the first drug that has received approval in Germany to treat SMA. Further therapeutic approaches such as the so-called "small molecules" or the gene replacement therapy are currently still being tested in clinical studies or are already waiting for approval by the European Medicines Agency (EMA). In this article, the most important disease-modifying drugs of SMA, the associated studies and their challenges are presented.

Vergleich der Befunde von 18-FDG- PET und CT beim prätherapeutischen Staging maligner Lymphome

Ziel: Vergleich der diagnostischen Aussagekraft von FDG-PET und CT zum Staging vor Therapie unter Berücksichtigung von Lokalisation, Durchmesser und Histologie der Läsion sowie Erfassung des FDG-Uptakes. Methoden: CT- und FDG-PET-Untersuchungen bei 27 Patienten mit histologisch gesichertem malignen Lymphom als Erstmanifestation oder Rezidiv wurden retrospektiv und unabhängig voneinander ausgewertet. CT-positive nodale Läsionen waren im Querdurchmesser (DCT) >15 mm. Bei visueller Auswertung in iterativ rekonstruierten PET-Studien gefundene fokale, unphysiologische FDG-Speicherungen wurden positiv gewertet und hinsichtlich Läsionsgröße (DPET) und partial-volumenkorrigierten standardisierten Uptake-Werten (SUV) quantifiziert. Eine Unterteilung der Läsionen erfolgte nach Histologie und Qualität (abgrenzbarer Lymphknoten, Konglomerattumor, extranodale Läsion). Ergebnis: CT beschrieb bei 26 Patienten 78 Läsionen, alle auch durch PET bestätigt. PET lokalisierte darüber hinaus weitere 18 Läsionen (+23%), bei hochmalignen Non-Hodgkin-Lymphomen (NHL) sogar +25%. Im Bereich des Halses sowie bei Lungenläsionen waren die Verfahren gleichwertig, bei der Beurteilung der übrigen Lymphknotenregionen sowie von Leber und Milz wies PET mehr Läsionen nach. Der SUV war bei hochmalignen NHL (19,0) signifikant höher als bei niedrigmalignen NHL und M. Hodgkin (10,6 bzw. 11,1). DCT und DPET korrelierten bei abgrenzbaren Lymphknoten signifikant (r = 0,75). Schlußfolgerung: FDG-PET ist der CT im Staging maligner Lymphome vor Therapie ebenbürtig bis überlegen. Hierzu ist eine qualitative Befundung ausreichend. Die zusätzliche quantitative Auswertung kann bei NHL einen Hinweis auf den Malignitätsgrad geben.

Trictide, a tricellulin-derived peptide to overcome cellular barriers

The majority of tight junction (TJ) proteins restrict the paracellular permeation of solutes via their extracellular loops (ECLs). Tricellulin tightens tricellular TJs (tTJs) and regulates bicellular TJ (bTJ) proteins. We demonstrate that the addition of recombinantly produced extracellular loop 2 (ECL2) of tricellulin opens cellular barriers. The peptidomimetic trictide, a synthetic peptide derived from tricellulin ECL2, increases the passage of ions, as well as of small and larger molecules up to 10 kDa, between 16 and 30 h after application to human epithelial colorectal adenocarcinoma cell line 2. Tricellulin and lipolysis-stimulated lipoprotein receptor relocate from tTJs toward bTJs, while the TJ proteins claudin-1 and occludin redistribute from bTJs to the cytosol. Analyzing the opening of the tricellular sealing tube by the peptidomimetic using super-resolution stimulated-emission depletion microscopy revealed a tricellulin-free area at the tricellular region. Cis-interactions (as measured by fluorescence resonance energy transfer) of tricellulin-tricellulin (tTJs), tricellulin-claudin-1, tricellulin-marvelD3, and occludin-occludin (bTJs) were strongly affected by trictide treatment. Circular dichroism spectroscopy and molecular modeling suggest that trictide adopts a β-sheet structure, resulting in a peculiar interaction surface for its binding to tricellulin. In conclusion, trictide is a novel and promising tool for overcoming cellular barriers at bTJs and tTJs with the potential to transiently improve drug delivery.

Real-world use, effectiveness and safety of anti-viral treatment in chronic hepatitis C genotype 3 infection

BACKGROUND

Treatment of chronic hepatitis C genotype 3 (GT3) is more challenging compared with other genotypes. Since 2014, several new treatment regimens have been approved but sometimes based on limited data.

AIM

To validate the use, effectiveness and safety of anti-viral treatment in chronic hepatitis C genotype 3 infection under real-word conditions.

METHODS

The German Hepatitis C-Registry is a large national non-interventional real-world study for patients with chronic hepatitis C. A total of 1322 GT3 patients were enrolled (211 untreated and 1111 treated patients).

RESULTS

Between February 2014 and September 2015, five different treatment strategies have been used (PegIFN+RBV, PegIFN+RBV+SOF, SOF+RBV, DCV+SOF±RBV, LDV/SOF±RBV). Treatment uptake and use of treatment concepts changed markedly and rapidly during the study influenced by new approvals, guideline recommendations, and label updates. PegIFN-based therapies constantly declined while DCV-based therapies increased with one interruption after the approval of LDV/SOF, which was frequently used until new guidelines recommended not using this combination for GT3. Per-protocol SVR ranged from 80.9% in the PegIFN+RBV group to 96.1% in PegIFN+RBV+SOF treated patients. Treatment-experienced patients with cirrhosis showed a suboptimal SVR of 68% for SOF+RBV but a high SVR of 90-95% for DCV+SOF±RBV. The safety analysis showed more adverse events and a stronger decline of haemoglobin for RBV containing regimens.

CONCLUSIONS

Real-world data can validate the effectiveness and safety for treatment regimens that had previously been approved with limited data, in particular for specific subgroups of patients. The present study demonstrates how rapid new scientific data, new treatment guidelines, new drug approvals and label changes are implemented into routine clinical practice today.

Redox Regulation of Cell Contacts by Tricellulin and Occludin: Redox-Sensitive Cysteine Sites in Tricellulin Regulate Both Tri- and Bicellular Junctions in Tissue Barriers as Shown in Hypoxia and Ischemia

Tight junctions (TJs) seal paracellular clefts in epithelia/endothelia and form tissue barriers for proper organ function. TJ-associated marvel proteins (TAMPs; tricellulin, occludin, marvelD3) are thought to be relevant to regulation. Under normal conditions, tricellulin tightens tricellular junctions against macromolecules. Traces of tricellulin occur in bicellular junctions.

AIMS

As pathological disturbances have not been analyzed, the structure and function of human tricellulin, including potentially redox-sensitive Cys sites, were investigated under reducing/oxidizing conditions at 3- and 2-cell contacts.

RESULTS

Ischemia, hypoxia, and reductants redistributed tricellulin from 3- to 2-cell contacts. The extracellular loop 2 (ECL2; conserved Cys321, Cys335) trans-oligomerized between three opposing cells. Substitutions of these residues caused bicellular localization. Cys362 in transmembrane domain 4 contributed to bicellular heterophilic cis-interactions along the cell membrane with claudin-1 and marvelD3, while Cys395 in the cytosolic C-terminal tail promoted homophilic tricellullar cis-interactions. The Cys sites included in homo-/heterophilic bi-/tricellular cis-/trans-interactions contributed to cell barrier tightness for small/large molecules.

INNOVATION

Tricellulin forms TJs via trans- and cis-association in 3-cell contacts, as demonstrated electron and quantified fluorescence microscopically; it tightens 3- and 2-cell contacts. Tricellulin's ECL2 specifically seals 3-cell contacts redox dependently; a structural model is proposed.

CONCLUSIONS

TAMP ECL2 and claudins' ECL1 share functionally and structurally similar features involved in homo-/heterophilic tightening of cell-cell contacts. Tricellulin is a specific redox sensor and sealing element at 3-cell contacts and may compensate as a redox mediator for occludin loss at 2-cell contacts in vivo and in vitro. Molecular interaction mechanisms were proposed that contribute to tricellulin's function. In conclusion, tricellulin is a junctional redox regulator for ischemia-related alterations.

Depletion of highly abundant proteins from human cerebrospinal fluid: a cautionary note

Affinity-based techniques, both for enrichment or depletion of proteins of interest, suffer from unwanted interactions between the bait or matrix material and molecules different from the original target. This effect was quantitatively studied by applying two common procedures for the depletion of albumin/gamma immunoglobulin to human cerebrospinal fluid. Proteins of the depleted and the column-bound fraction were identified by mass spectrometry, employing (18)O labeling for quantitation of their abundance. To different extents, the depletion procedures caused the loss of proteins previously suggested as biomarker candidates for neurological diseases. This is an important phenomenon to consider when quantifying protein levels in biological fluids.

Redox-sensitive structure and function of the first extracellular loop of the cell-cell contact protein claudin-1: lessons from molecular structure to animals

The paracellular cleft within epithelia/endothelia is sealed by tight junction (TJ) proteins. Their extracellular loops (ECLs) are assumed to control paracellular permeability and are targets of pathogenes. We demonstrated that claudin-1 is crucial for paracellular tightening. Its ECL1 is essential for the sealing and contains two cysteines conserved throughout all claudins.

AIMS

We prove the hypothesis that this cysteine motif forms a redox-sensitive intramolecular disulfide bridge and, hence, the claudin-1-ECL1 constitutes a functional structure which is associated to ECLs of this and other TJ proteins.

RESULTS

The structure and function of claudin-1-ECL1 was elucidated by investigating sequences of this ECL as synthetic peptides, C1C2, and as recombinant proteins, and exhibited a β-sheet binding surface flanked by an α-helix. These sequences bound to different claudins, their ECL1, and peptides with nanomolar binding constants. C-terminally truncated C1C2 (-4aaC) opened cellular barriers and the perineurium. Recombinant ECL1 formed oligomers, and bound to claudin-1 expressing cells. Oligomerization and claudin association were abolished by reducing agents, indicating intraloop disulfide bridging and redox sensitivity.

INNOVATION

The structural and functional model based on our in vitro and in vivo investigations suggested that claudin-1-ECL1 constitutes a functional and ECL-binding β-sheet, stabilized by a shielded and redox-sensitive disulfide bond.

CONCLUSION

Since the β-sheet represents a consensus sequence of claudins and further junctional proteins, a general structural feature is implied. Therefore, our model is of general relevance for the TJ assembly in normal and pathological conditions. C1C2-4aaC is a new drug enhancer that is used to improve pharmacological treatment through tissue barriers.

Highly conserved cysteines are involved in the oligomerization of occludin-redox dependency of the second extracellular loop

The tight junction (TJ) marker occludin is a 4-transmembrane domain (TMD) protein with unclear physiological and pathological functions, interacting with other TJ proteins. It oligomerizes and is redox sensitive. However, oligomerization sites and mechanisms are unknown.

AIMS

To identify hypoxia-sensitive binding sites, we investigated the consequences of amino-acid substitutions of highly conserved cysteines in human occludin, under normal and hypoxic incubations.

RESULTS

(i) The extracellular loop 2 (ECL2) showed homophilic trans- and cis-association between opposing cells and along the cell membrane, respectively, caused by a loop properly folded via an intraloop disulfide bridge between the shielded C216 and C237. Hypoxia and reductants prevented the associations. (ii) C82 in TMD1 directly cis-associated without disulfide formation. (iii) C76 in TMD1 and C148 in TMD2 limited the trans-interaction; C76 also limited occludin-related paracellular tightness and changed the strand morphology of claudin-1. (iv) The diminished binding strength found after substituting C82, C216, or C237 was accompanied by increased occludin mobility in the cell membrane.

INNOVATION

The data enable the first experimentally proven structural model of occludin and its homophilic interaction sites, in which the ECL2, via intraloop disulfide formation, has a central role in occludin's hypoxia-sensitive oligomerization and to regulate the structure of TJs.

CONCLUSION

Our findings support the new concept that occludin acts as a hypoxiasensor and contributes toward regulating the TJ assembly redox dependently. This is of pathogenic relevance for tissue barrier injury with reducing conditions. The ECL2 disulfide might be a model for four TMD proteins in TJs with two conserved cysteines in an ECL.

Quality of life after liver transplantation

Quality of life (QoL) is an outcome criterion of increasing importance after orthotopic liver transplantation (OLT). The background of this development is the dramatic improvement in patient survival rates over the past two decades combined with the question of the quality of this survival. Among 339 OLT performed in Kiel since 1987, 123 recipients (70 males, 53 females) of mean age 56.7 +/- 13.1 years who underwent transplantation between August 1992 and June 2007 were subjected to European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ) C30 plus a liver transplant specific module to analyze QoL. In addition, we included 40 patients listed for OLT in the univariate and multivariate analyses performed using SPSS13.0. A cohort of healthy individuals served as the control group. QoL (global health) among liver recipients was reduced compared with the control group and improved compared with patients on the waiting list. Comparison of the underlying liver diseases showed a comparable QoL between postalcoholic cirrhosis and cholestatic liver diseases. Retransplantation was accompanied by a significant loss of QoL. Cyclosporine-treated recipients displayed a better QoL compared with those treated with tacrolimus. After establishing a system of continuous, systematic QoL assessment, we combined these results with survival outcomes. Further research must focus on advanced statistical methodology that combines these 2 major outcome parameters (QoL and survival). Furthermore, the influence of medical parameters, such of co-morbidity or immunosuppression, needs to be further established with reference to QoL.

Two germ cell lineages with genomes of different species in one and the same animal

Cytological evidence for two germ cell lineages, each with the DNA-content of one of the parental species only, was obtained for certain males of the hybridogenic water frog Rana esculenta (R. ridibunda x R. lessonae) by means of DNA flow cytometry. The approach was based on the 16 +/- 2% difference in the DNA-content of genomes of the parental species. Two types of germ cells were observed in six out of 39 males studied from populations where such males did exist. The term 'hybrid amphispermy' is proposed for the phenomenon. Occurrence of the 'hybrid amphispermy' suggests that the direction of elimination (i.e., which genome being eliminated) is determined in R. esculenta by the relative activity of putative elimination-inducing factor(s) in each of the parental genomes, which can alternate from cell to cell.

[Inflammatory reactions in the wear particle induced and infectious periprosthetic membrane of loosened hip- and knee endoprostheses: pathogenetic relevance of differentially expressed genes cd9, cd11b, cd18, cd52 and pdgfrbeta]

BACKGROUND

A previous cDNA-microarray analysis described constantly differentially expressed genes in wear particle induced and infectious SLIM (synovial-like interface membrane). This study aims to validate the cDNA microarray data in order to approve differences of the gene expression profiles of RNA and proteins.

METHODS

Tissue from 16 wear particle induced and 20 infectious periprosthetic membranes were analyzed by RT-PCR and immunohistology with regard to the expression of inflammatoric associated genes.

RESULTS

RT-PCR showed the genes cd9, cd11b, cd18, cd52 as well as pdgfrbeta in interface membranes. In the wear particle induced membrane the immunohistochemical analysis showed a significantly weaker gene expression of PDGFRbeta, whereas the differential overexpression of CD9, CD11b and CD52 was confirmed. For CD18, there was no difference in expression between wear induced and infectious periprosthetic tissue.

CONCLUSION

Different pathomechanisms, which are reflected by different gene expression profiles, might produce different types of periprosthetic membranes. By RT-PCR and immunohistochemical analysis the micro array data of the genes cd9, cd11b, cd52 and pdgfrbeta could be validated. Identifying the gene products of cd9, cd11b and cd52 in blood or tissue may help to differentiate between wear induced and infectious loosening.

Avalanche dynamics, surface roughening, and self-organized criticality: Experiments on a three-dimensional pile of rice

We present a two-dimensional system that exhibits features of self-organized criticality. The avalanches that occur on the surface of a pile of rice are found to exhibit finite size scaling in their probability distribution. The critical exponents are tau=1.21(2) for the avalanche size distribution and D=1.99(2) for the cutoff size. Furthermore, the geometry of the avalanches is studied, leading to a fractal dimension of the active sites of d(B)=1.58(2). Using a set of scaling relations, we can calculate the roughness exponent alpha=D-d(B)=0.41(3) and the dynamic exponent z=D(2-tau)=1.56(8). This result is compared with that obtained from a power-spectrum analysis of the surface roughness, which yields alpha=0.42(3) and z=1.5(1) in excellent agreement with those obtained from the scaling relations.