Recurrence of primary sclerosing cholangitis after liver transplantation is associated with specific changes in the gut microbiome pretransplant – a pilot study

Primary sclerosing cholangitis (PSC) is a common indication for liver transplantation (LT). Up to 25% of patients experience recurrence of PSC (rPSC) after LT, which is associated with significant morbidity and mortality. To date, it is not possible to predict which patients are at risk for rPSC. The aetiology of PSC is complex and is speculated to involve translocation of intestinal bacteria to the liver, because of its frequent co-occurrence with inflammatory bowel diseases (IBD). Here, we investigate whether the mucosal intestinal microbiome of PSC patients (n = 97) at time of first LT can identify those patients who will develop rPSC. 16S gene sequencing of bacterial DNA isolated from formalin-fixed paraffin-embedded biopsies showed that PSC patients with Crohn’s disease (n = 15) have a reduced microbial diversity and that inflammation of the mucosa is associated with beta-diversity changes and feature differences. No differences in alpha- or beta diversity were observed between patients with rPSC (n = 14) and without rPSC (n = 83). However, many over-represented bacterial features were detected in patients with rPSC, while surprisingly, those without recurrence of disease were characterized by an increased presence of the Gammaproteobacteria Shigella. This pilot study warrants further investigation into bacterial differences between rPSC and non-rPSC patients.     

Komplikationsmanagement bei der Deszensus- und Inkontinenzchirurgie

Tension-free alloplastic slings (TFAS) have revolutionized surgery for female stress urinary incontinence for more than 20 years. The procedure is easy to perform, minimally invasive with a short operating time in an outpatient setting and has proven efficacy comparable to retropubic colposuspension. The frequency of surgery for female stress incontinence has tripled within one decade which has to have an impact on the number of complications. In contrast, sacrocolpopexy has remained the gold standard in urological prolapse surgery as none of the new techniques has reached similar efficacy or safety; however, possible complications have to be named and their causes have to be understood to maintain the highest quality of care in the future. Possible complications of TFAS are potentially underestimated with respect to prevalence and manageability. Possible complications of prolapse and incontinence surgery are presented and the underlying causes are identified. Knowledge of the pathophysiology and the cause of complications together with the results of a postoperative diagnostic work-up, allow complication management to be tailored to each individual patient. To prevent complications all conservative treatment options should have been tried preoperatively and a complete evaluation (including urodynamics) should have been carried out for every patient. Postoperative urodynamics may help to document treatment success and to identify and quantify complications.     

Efficacy of Anti-inflammatory Agents to Improve Symptoms in Patients With Schizophrenia: An Update

Background: The inflammatory hypothesis of schizophrenia is not new, but recently it has regained interest because more data suggest a role of the immune system in the pathogenesis of schizophrenia. If increased inflammation of the brain contributes to the symptoms of schizophrenia, reduction of the inflammatory status could improve the clinical picture. Lately, several trials have been conducted investigating the potential of anti-inflammatory agents to improve symptoms of schizophrenia. This study provides an update regarding the efficacy of anti-inflammatory agents on schizophrenic symptoms in clinical studies performed so far. Methods: An electronic search was performed using PubMed, Embase, the National Institutes of Health web site http://www.clinicaltrials.gov, Cochrane Schizophrenia Group entries in PsiTri, and the Cochrane Database of Systematic Reviews. Only randomized, double-blind, placebo-controlled studies that investigated clinical outcome were included. Results: Our search yielded 26 double-blind randomized controlled trials that provided information on the efficacy on symptom severity of the following components: aspirin, celecoxib, davunetide, fatty acids such as eicosapentaenoic acids and docosahexaenoic acids, estrogens, minocycline, and N-acetylcysteine (NAC). Of these components, aspirin (mean weighted effect size [ES]: 0.3, n = 270, 95% CI: 0.06–0.537, I² = 0), estrogens (ES: 0.51, n = 262, 95% CI: 0.043–0.972, I² = 69%), and NAC (ES: 0.45, n = 140, 95% CI: 0.112–0.779) showed significant effects. Celecoxib, minocycline, davunetide, and fatty acids showed no significant effect. Conclusion: The results of aspirin addition to antipsychotic treatment seem promising, as does the addition of NAC and estrogens. These 3 agents are all very broadly active substances, and it has to be investigated if the beneficial effects on symptom severity are indeed mediated by their anti-inflammatory aspects.Key words: add-on antipsychotic therapy, aspirin, N-acetylcysteine, estrogens     

Adenylyl Cyclase 6 Deficiency Ameliorates Polycystic Kidney Disease

cAMP is an important mediator of cystogenesis in polycystic kidney disease (PKD). Several adenylyl cyclase (AC) isoforms could mediate cAMP accumulation in PKD, and identification of a specific pathogenic AC isoform is of therapeutic interest. We investigated the role of AC6 in a mouse model of PKD that is homozygous for the loxP-flanked PKD1 gene and heterozygous for an aquaporin-2-Cre recombinase transgene to achieve collecting duct-specific gene targeting. Collecting duct-specific knockout of polycystin-1 caused massive renal cyst formation, kidney enlargement, and severe kidney failure, with a mean survival time of 2 months. In contrast, coincident collecting duct-specific knockout of polycystin-1 and AC6 (also homozygous for the floxed ADCY6 gene) markedly decreased kidney size and cystogenesis, improved renal function, reduced activation of the B-Raf/ERK/MEK pathway, and greatly increased survival. Absence of collecting duct AC6 did not alter urinary cAMP excretion or kidney cAMP concentration. In conclusion, AC6 is a key mediator of cyst formation and renal injury in a model of PKD.Polycystic kidney disease (PKD) is the fourth leading cause of ESRD in the United States. Renal cyst development and expansion in PKD critically depend on vasopressin (AVP).¹ Crossing Brattleboro rats, which have no AVP, with autosomal recessive PKD rats markedly inhibits cystogenesis, whereas an AVP analog restores the cystic phenotype.² The recent Tolvaptan Efficacy and Safety in Management of Autosomal Dominant Polycystic Kidney Disease and Its Outcomes trial found that the AVP V2 receptor antagonist tolvaptan slowed the increase in kidney volume and the decline in kidney function in PKD patients over a 3-year period.³ The cystic effect of AVP is likely caused in large part by stimulation of cAMP.¹ In cells from PKD kidneys, cAMP agonism stimulates cell growth, whereas in normal cells, cAMP inhibits cell growth.¹ The mechanism of cAMP-stimulated cell proliferation has been largely ascribed to protein kinase A activation of the B-Raf/mitogen activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway.^1,4 Intracellular Ca²⁺ may be important in determining the effect of cAMP on cell proliferation: under normal conditions, Akt, a serine-threonine protein kinase, inhibits B-Raf (another serine-threonine protein kinase); however, in PKD cells, intracellular Ca²⁺ is reduced, which decreases Akt activity, permitting cAMP activation of B-Raf.¹ In addition, cyst fluid secretion is driven by chloride transport stimulated by cAMP.^1,4 Thus, cAMP is a key factor in cyst formation and enlargement, and AVP is important in driving cAMP formation.The renal collecting duct (CD) is the major source of cysts in humans and animal models of autosomal dominant PKD and autosomal recessive PKD.¹ Given that cAMP plays a central role in the pathogenesis of PKD, it would be important to define which adenylyl cyclase (AC) isoforms are involved in AVP-mediated cyst formation in the CD. The CD contains intercalated and principal cells. Only principal cells give rise to cysts in mouse models of CD PKD1 deficiency, and only AC3, AC4, and AC6 are expressed in mouse principal cells.⁵ It is unknown which of these three AC isoforms is involved in AVP-stimulated cyst formation in the CD; however, AC3 and/or AC6 may be particularly important, because their expression has been localized to primary cilia (albeit in nonprincipal cells^6,7), the cellular organelle found to be critically important in controlling cyst development.⁸To begin to evaluate the role of individual AC isoforms in PKD renal disease, we have now studied mouse models of polycystin-1 deficiency with or without AC6 deficiency. Given that no specific AC isoform inhibitors exist (although this area represents an active area of drug development⁹), a genetic engineering approach was used. We previously reported a mouse model of PKD by selectively deleting the Pkd1 gene in CD principal cells.^10,11 In this model, mice containing loxP sites within introns 1 and 4 of the Pkd1 gene are bred with mice transgenic for the aquaporin-2 promoter driving expression of Cre recombinase (AQP2-Cre); the AQP2 promoter is expressed in the kidney only within principal cells. In the current study, we found that mice with homozygous Pkd1 gene disruption in the CD (PKD knockout [KO]) have multiple large cysts and markedly enlarged kidneys at 33 days of age (Figure 1A). The mean survival was 59±6 days (Figure 1B), and BUN, used as an indicator of renal function, was greatly elevated (135±8 mg/dl) (Figure 1C). Thus, mice with homozygous Pkd1 gene disruption in the CD had rapid cyst progression, marked renal failure, and early mortality.Open in a separate windowFigure 1.AC6 KO improves survival and lessens kidney disease in PKD KO mice. Coincident AC6 KO reduced kidney and cyst size. A shows representative images from 15 different kidneys of each genotype. B shows activated caspase 3 (apoptosis) or proliferating cell nuclear antigen (PCNA; proliferation), both of which are green, and AQP2 (red; to help show cyst walls, although not all cyst walls are red) staining in representative kidney sections from five different kidneys of each genotype. C shows mouse survival probability (all animals are PKD KO; legend shows AC6 genotype; n=26–52 per data point). D shows BUN at 33 days of age (n=15–27). *P<0.05 versus PKD KO alone.To examine the role of AC6 in PKD, mice were generated with targeted homozygous disruption of both the Pkd1 and adenylyl cyclase 6 (ADCY6) genes. Mice with loxP-flanked exons 3–12 of the ADCY6 gene, which encode the first catalytic domain, were used (we previously reported CD-specific KO of AC6; these mice have a mild urinary concentrating defect and normal renal histology at 1 year of age¹²). A key feature of these double KO mice (PKD/AC6 KO) is that the Pkd1 and ADCY6 genes are deleted in the same cells (i.e., whenever Cre is expressed); regardless of whether 100% of principal cells are affected, both target genes have an extremely high likelihood of undergoing recombination. Notably, kidney polycystin-1 mRNA levels were similar between PKD KO and PKD/AC6 KO mice (Figure 1, Figure 1). PKD/AC6 KO mice manifested greatly increased survival compared with PKD KO mice (Figure 1). When PKD/AC6 KO mice died, the average age of death was 209±11 days; however, approximately one third of mice were alive at 1 year. The increased survival was associated with markedly reduced BUN (36±2 mg/dl) compared with PKD KO animals (Figure 1). Mice homozygous for PKD KO but heterozygous for AC6 KO had an intermediate survival time (Figure 1).

Table 1.

Effect of AC6 KO on kidney parameters in PKD KO mice

Genetic variation in the 22q11 locus and susceptibility to schizophrenia

An increased prevalence of microdeletions at the 22q11 locus has been reported in samples of patients with schizophrenia. 22q11 microdeletions represent the highest known genetic risk factor for the development of schizophrenia, second only to that of the monozygotic cotwin of an affected individual or the offspring of two schizophrenic parents. It is therefore clear that a schizophrenia susceptibility locus maps to chromosome 22q11. In light of evidence for suggestive linkage for schizophrenia in this region, we hypothesized that, whereas deletions of chromosome 22q11 may account for only a small proportion of schizophrenia cases in the general population (up to approximately 2%), nondeletion variants of individual genes within the 22q11 region may make a larger contribution to susceptibility to schizophrenia in the wider population. By studying a dense collection of markers (average one single nucleotide polymorphism20 kb over 1.5 Mb) in the vicinity of the 22q11 locus, in both family- and population-based samples, we present here results consistent with this assumption. Moreover, our results are consistent with contribution from more than one gene to the strikingly increased disease risk associated with this locus. Finer-scale haplotype mapping has identified two subregions within the 1.5-Mb locus that are likely to harbor candidate schizophrenia susceptibility genes.     

The severe combined immunodeficient-human peripheral blood stem cell (SCID-huPBSC) mouse: a xenotransplant model for huPBSC-initiated hematopoiesis

Mononuclear cells (MNCs) containing peripheral blood stem cells (PBSCs) were obtained from solid-tumor patients undergoing mobilizing chemotherapy followed by granulocyte colony-stimulating factor for PBSC transplantation-supported dose-intensified anticancer chemotherapy and were transplanted into unconditioned "nonleaky" young severe combined immunodeficient mice. Multilineage engraftment was shown by flow cytometry and immunocytochemistry using monoclonal antibodies to various human cell surface antigens as well as identification of human immunoglobulin in murine sera. Within a dose range of MNCs suitable for transplantation (10 to 36 x 10(6) cells/graft) the number of CD34+ cells injected (optimal at > 0.7 x 10(6)/graft) determined the yield of human cells produced in recipient animals. Engraftment of hu PBSC preparations resulted in prolonged generation of physiologic levels of human cytokines including interleukin-3 (IL-3), IL-6, and granulocyte- macrophage colony-stimulating factor, which were detectable in the murine blood over a period of at least 4 months. In vivo survival of immature human progenitor cells was preserved even 9 months after transplantation. Because human IL-3 is known to stimulate early hematopoiesis, a rat fibroblast cell line was stably transfected with a retroviral vector carrying the human IL-3 gene and cotransplanted subcutaneously as additional source of growth factor. Cotransplants of this cell line producing sustained in vivo levels of circulating human IL-3 for at least 12 weeks significantly accelerated the process of engraftment of huPBSC and spurred the spread of mature human cells to the murine spleen, liver, thymus, and peripheral blood. Cotransplants of allogeneic human bone marrow stromal cells derived from long-term cultures resulted in a comparable--though less prominent--support of engraftment.     

Six months of recombinant human GH therapy in patients with ischemic cardiac failure does not influence left ventricular function and mass

Beneficial effects of recombinant human GH on cardiac function have been reported in humans with GH deficiency and in patients with idiopathic dilated cardiomyopathy. No randomized controlled trial has been performed on the effects of recombinant human GH on cardiac function in patients with ischemic cardiac failure. We therefore randomly assigned 22 patients with ischemic cardiac failure (left ventricular ejection fraction, <40%; 19 men and 3 women; mean age, 64 yr) to receive 6 months of unblinded therapy with recombinant human GH (2.0 IU/d) or no treatment. Primary end points were left ventricular ejection fraction and left ventricular mass. Left ventricular end-diastolic volume, left ventricular end-systolic volume, and myocardial perfusion, both at rest and during exercise, were assessed as well. Cardiac imaging techniques were electrocardiographically gated single photon emission computer tomography and magnetic resonance imaging. In addition, biochemical and biometric measurements were performed. Nineteen patients completed the study (10 controls and 9 GH-treated subjects). IGF-I and IGF-binding protein-3 increased significantly after recombinant human GH treatment (+24% and +58%, respectively) compared with control values (-14% and +5%; P < 0.05). Left ventricular ejection fraction, left ventricular end-diastolic volume, left ventricular end-systolic volume, left ventricular mass, and myocardial perfusion were not influenced by recombinant human GH therapy. We conclude that 6 months of recombinant human GH treatment in patients with ischemic cardiac failure had no beneficial effect on left ventricular function and mass.