Oxygen persufflation as adjunct in liver preservation (OPAL): Study protocol for a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Early graft dysfunction due to preservation/reperfusion injury represents a dramatic event after liver transplantation. Enhancement of donor organ criteria, in order to cope with the ever increasing donor shortage, further increases graft susceptibility to ischemic alterations.</p> <p>Major parts of post-preservation injury, however, occur at the time of warm reperfusion but not during ischemic storage; successful reperfusion of ischemic tissue in turn depends on an adequate redox and intracellular signal homeostasis. The latter has been shown experimentally to be favorably influenced by oxygen persufflation within short time spans. Thus viability of marginally preserved liver grafts could still be augmented by transient hypothermic reconditioning <b><it>even after </it></b>normal procurement and static cold storage. The present study is aimed to confirm the conceptual expectations, that hypothermic reconditioning by gaseous oxygen persufflation is a useful method to suppress injurious cellular activation cascades and to improve post-ischemic recovery of marginally preserved liver grafts.</p> <p>Methods/Design</p> <p>OPAL is a prospective single center randomized proof of concept study, including two parallel groups in a total of 116 liver transplant patients. The effect of an in hospital treatment of the isolated liver graft by 2 hours of oxygen persufflation immediately prior to transplantation will be assesses as compared to standard procedure (cold storage without further intervention). The primary endpoint is the peak transaminase serum level (AST) during the first three days after transplantation as a surrogate readout for parenchymal liver injury. Other outcomes comprise patient and graft survival, time of intensive care requirement, hepatic tissue perfusion 1h after revascularisation, early onset of graft dysfunction based on coagulation parameters, as well as the use of a refined scoring-system for initial graft function based on a multi-parameter (AST, ALT, Quick and bilirubin) score. Furthermore, the effect of OPAL on molecular pathways of autophagy and inflammatory cell activation will be evaluated. Final analysis will be based on all participants as randomized (intention to treat).</p> <p>Trial Registration</p> <p>Current Controlled Trials <a href="http://www.controlled-trials.com/ISRCTN00167887">ISRCTN00167887</a></p

A Large Expansion of the HSFY Gene Family in Cattle Shows Dispersion across Yq and Testis-Specific Expression

Heat shock transcription factor, Y-linked (HSFY) is a member of the heat shock transcriptional factor (HSF) family that is found in multiple copies on the Y chromosome and conserved in a number of species. Its function still remains unknown but in humans it is thought to play a role in spermatogenesis. Through real time polymerase chain reaction (PCR) analyses we determined that the HSFY family is largely expanded in cattle (∼70 copies) compared with human (2 functional copies, 4 HSFY-similar copies). Unexpectedly, we found that it does not vary among individual bulls as a copy number variant (CNV). Using fluorescence in situ hybridization (FISH) we found that the copies are dispersed along the long arm of the Y chromosome (Yq). HSFY expression in cattle appears restricted to the testis and its mRNA correlates positively with mRNA markers of spermatogonial and spermatocyte cells (UCHL1 and TRPC2, respectively) which suggests that HSFY is expressed (at least in part) in early germ cells

ZNF280BY and ZNF280AY: autosome derived Y-chromosome gene families in Bovidae

<p>Abstract</p> <p>Background</p> <p>Recent progress in exploring the Y-chromosome gene content in humans, mice and cats have suggested that "autosome-to-Y" transposition of the male fertility genes is a recurrent theme during the mammalian Y-chromosome evolution. These transpositions are lineage-dependent. The purpose of this study is to investigate the lineage-specific Y-chromosome genes in bovid.</p> <p>Results</p> <p>We took a direct testis cDNA selection strategy and discovered two novel gene families, <it>ZNF280BY </it>and <it>ZNF280AY</it>, on the bovine (<it>Bos taurus</it>) Y-chromosome (BTAY), which originated from the transposition of a gene block on the bovine chromosome 17 (BTA17) and subsequently amplified. Approximately 130 active <it>ZNF280BY </it>loci (and ~240 pseudogenes) and ~130 pseudogenized <it>ZNF280AY </it>copies are present over the majority of the male-specific region (MSY). Phylogenetic analysis indicated that both gene families fit with the "birth-and-death" model of evolution. The active <it>ZNF280BY </it>loci share high sequence similarity and comprise three major genomic structures, resulted from insertions/deletions (indels). Assembly of a 1.2 Mb BTAY sequence in the MSY ampliconic region demonstrated that <it>ZNF280BY </it>and <it>ZNF280AY</it>, together with <it>HSFY </it>and <it>TSPY </it>families, constitute the major elements within the repeat units. The <it>ZNF280BY </it>gene family was found to express in different developmental stages of testis with sense RNA detected in all cell types of the seminiferous tubules while the antisense RNA detected only in the spermatids. Deep sequencing of the selected cDNAs revealed that different loci of <it>ZNF280BY </it>were differentially expressed up to 60-fold. Interestingly, different copies of the <it>ZNF280AY </it>pseudogenes were also found to differentially express up to 10-fold. However, expression level of the <it>ZNF280AY </it>pseudogenes was almost 6-fold lower than that of the <it>ZNF280BY </it>genes. <it>ZNF280BY </it>and <it>ZNF280AY </it>gene families are present in bovid, but absent in other mammalian lineages.</p> <p>Conclusions</p> <p><it>ZNF280BY </it>and <it>ZNF280AY </it>are lineage-specific, multi-copy Y-gene families specific to <it>Bovidae</it>, and are derived from the transposition of an autosomal gene block. The temporal and spatial expression patterns of <it>ZNF280BY</it>s in testis suggest a role in spermatogenesis. This study offers insights into the genomic organization of the bovine MSY and gene regulation in spermatogenesis, and provides a model for studying evolution of multi-copy gene families in mammals.</p

Genetic causes and treatment of spermatogenic failure

The vast majority of cases of spermatogenic failure, defined as no sperm in semen or low semen quality, are idiopathic, although several genetic factors have been identified. In this thesis, we focused on the effect of Y-chromosome variation including TSPY copy number and AZFc deletions on semen quality and studied the effectiveness and safety of in vitro spermatogonial stem cell propagation for (SSC) transplantation as a potential treatment for spermatogenic failure by increasing the number of SSCs. We found that the variation in TSPY copy number is not associated with total motile sperm count and therefore has no functional consequences for semen quality. AZFc deletions are known to be common genetic causes of spermatogenic failure. We showed that in our previously established culture system, the AZFc-deleted spermatogonia behave similar as spermatogonia from non-deleted men. To further characterize the human SSCs in our culture, we investigated which marker is efficient in enriching for SSCs. We found that ITGA6 (using magnetic assisted cell sorting or MACS) is an efficient method for enrichment of SSCs. We then investigated the genetic and epigenetic stability of human SSCs after long-term culture and showed that genetic stability of SSCs is preserved during culture. However, the methylation status of some of the imprinted genes is changed, which requires further investigation. We concluded that in vitro propagation of human SSCs followed by transplantation could be a good potential treatment option in patients with a low number of functional SSCs due to genetically caused spermatogenic failure

AZFc deletions do not affect the function of human spermatogonia in vitro

Azoospermic factor c (AZFc) deletions are the underlying cause in 10% of azoo- or severe oligozoospermia. Through extensive molecular analysis the precise genetic content of the AZFc region and the origin of its deletion have been determined. However, little is known about the effect of AZFc deletions on the functionality of germ cells at various developmental steps. The presence of normal, fertilization-competent sperm in the ejaculate and/or testis of the majority of men with AZFc deletions suggests that the process of differentiation from spermatogonial stem cells (SSCs) to mature spermatozoa can take place in the absence of the AZFc region. To determine the functionality of AZFc-deleted spermatogonia, we compared in vitro propagated spermatogonia from six men with complete AZFc deletions with spermatogonia from three normozoospermic controls. We found that spermatogonia of AZFc-deleted men behave similar to controls during culture. Short-term (18 days) and long-term (48 days) culture of AZFc-deleted spermatogonia showed the same characteristics as non-deleted spermatogonia. This similarity was revealed by the same number of passages, the same germ cell clusters formation and similar level of genes expression of spermatogonial markers including ubiquitin carboxyl-terminal esterase L1 (UCHL1), zinc finger and BTB domain containing 16 (ZBTB16) and glial cell line-derived neurotrophic factor family receptor alpha 1 (GFRA1), as well as germ cell differentiation markers including signal transducer and activator of transcription 3 (STAT3), spermatogenesis and oogenesis specific basic helix-loophelix 2 (SOHLH2), v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) and synaptonemal complex protein 3 (SYCP3). The only exception was melanoma antigen family A4 (MAGEA4) which showed significantly lower expression in AZFc-deleted samples than controls in short-term culture while in long-term culture it was hardly detected in both AZFc-deleted and control spermatogonia. These data suggest that, at least in vitro, spermatogonia of AZFc-deleted men are functionally similar to spermatogonia from non-deleted men. Potentially, this enables treatment of men with AZFc deletions by propagating their SSCs in vitro and autotransplanting these SSCs back to the testes to increase sperm counts and restore fertilit