Parkin cooperates with GDNF/RET signaling to prevent dopaminergic neuron degeneration

Parkin and the glial cell line–derived neurotrophic factor (GDNF) receptor RET have both been independently linked to the dopaminergic neuron degeneration that underlies Parkinson’s disease (PD). In the present study, we demonstrate that there is genetic crosstalk between parkin and the receptor tyrosine kinase RET in two different mouse models of PD. Mice lacking both parkin and RET exhibited accelerated dopaminergic cell and axonal loss compared with parkin-deficient animals, which showed none, and RET-deficient mice, in which we found moderate degeneration. Transgenic expression of parkin protected the dopaminergic systems of aged RET-deficient mice. Downregulation of either parkin or RET in neuronal cells impaired mitochondrial function and morphology. Parkin expression restored mitochondrial function in GDNF/RET-deficient cells, while GDNF stimulation rescued mitochondrial defects in parkin-deficient cells. In both cases, improved mitochondrial function was the result of activation of the prosurvival NF-κB pathway, which was mediated by RET through the phosphoinositide-3-kinase (PI3K) pathway. Taken together, these observations indicate that parkin and the RET signaling cascade converge to control mitochondrial integrity and thereby properly maintain substantia nigra pars compacta dopaminergic neurons and their innervation in the striatum. The demonstration of crosstalk between parkin and RET highlights the interplay in the protein network that is altered in PD and suggests potential therapeutic targets and strategies to treat PD.     

Motivation for and adherence to growth hormone replacement therapy in adults with hypopituitarism: the patients‘ perspective

Pituitary - While reasons for non-adherence in children requiring growth hormone (GH) replacement (GH-Rx) are well researched, few studies have investigated adherence in adult GH deficient...     

A framework to start the debate on neonatal screening policies in the EU: an Expert Opinion Document

The European Union (EU) Council Recommendation on rare diseases urged the member states to implement national and EU collaborative actions to improve the health care of rare disease patients. Following this recommendation, the European Commission launched a tender on newborn screening (NBS) to report on current practices of laboratory testing, form a network of experts and provide guidance on how to further implement NBS screening in a responsible way, the latter of which was provided in an Expert Opinion document. After consultation of experts from EU member states, (potential) candidate member states and European Free Trade Association countries, in a consensus meeting in June 2011, 70 expert opinions were finalized. They included the need to develop case definitions for all disorders screened for to facilitate assessment and international outcome studies. Decision whether a screening program should be performed can be based on screening criteria updated from the traditional Wilson and Jungner (1968) criteria, relating to disease, treatment, test and cost. The interest of the child should be central in the assessment of pros and cons. A European NBS body should assess evidence on (new) screening candidate disorders. For rare conditions, best level evidence should be used. The health system should ensure treatment to cases diagnosed by screening, controlled and revised by follow-up outcome studies. Screening methodology should aim to avoid unintended findings, such as mild forms and carrier status information, as much as possible. Activities to improve NBS in Europe, such as training and scientific evaluation, could benefit from collaboration at EU level and beyond.The European Union (EU) Council Recommendation¹ on Rare Diseases (9 June 2009)² identified rare diseases (ie, a life-threatening or chronically debilitating condition affecting not more than five in 10 000 persons in the community) as a public health concern and highlighted the need for public health actions, promoting the development of research on rare disorders and the improvement of the health care of rare disease patients. Following this recommendation, the European Commission launched a tender on neonatal screening (=newborn screening, NBS) in July 2009 (http://ec.europa.eu/eahc/health/tenders_H09C2.html) in order to (1) report on the practices of neonatal screening for rare disorders implemented in all the member states, including number of centers, estimate the number of infants screened and the number of disorders included in the NBS, as well as reasons for the selection of these disorders, (2) to identify types of medical management and follow-up implemented in the member states, (3) to establish a network of experts analyzing the information and formulating a final opinion containing recommendations on best practices, and recommending a core panel of NBS conditions that could be included in all MS practices, and (4) to develop a decision-making matrix that could be used by member states'' programs to systematically expand (or contract) screening mandates.The focus of the tender activities was on NBS by using laboratory testing techniques (blood spot screening). All reports are available on the internet (http://www.iss.it/cnmr/prog/cont.php?id=1621&lang=1&tipo=64).To get some insight into the current practices (points 1 and 2 above), an online survey was compiled and filled out by EU member states, (potential) member states and European Free Trade Association countries – in total 40 countries. Apart from the final report, available on the internet, the current practices are summarized in two journal articles: the first publication addresses the steps in screening programmes from blood spot to screening result³ and the second publication addresses the steps from screening laboratory results to treatment, follow-up and quality assurance.⁴As a third part of the activity and work methodology requested by the tender specifications, a European Union Network of Experts on Newborn Screening (EUNENBS) had to be constituted. Criteria for the inclusion of experts in EUNENBS (http://www.iss.it/cnmr/prog/cont.php?id=1621&lang=1&tipo=64) include that all member states'' authorities should be represented in the network. Each countries'' competent authorities were invited to identify their experts to represent the country at the workshops in 2010 and 2011. Further experts represent European professional and scientific organizations involved in NBS, the representative of the US Secretary''s Advisory Committee on Heritable Disorders in Newborns and Children, additional fields of expertise (eg, ethics) and patient organizations. The list of EUNENBS members is available as Appendix 1 of the Expert Opinion document (http://www.iss.it/cnmr/prog/cont.php?id=1621&lang=1&tipo=64). Most EUNENBS members have a background in health policy making, health technology assessment (HTA) and/or coordinating screening programs, many are involved in the service delivery of NBS in pediatrics, laboratory medicine and genetics. The task of EUNENBS was to supervise the work of the tender and participate in the revision of the tender deliverables, including the Expert Opinion document. The EUNENBS members have provided informally their input and advice without implying any obligation or commitment of their national authorities or organizations. Working documents were prepared reviewing most relevant scientific literature on the development of NBS policy and submitted to EUNENBS to stimulate the discussion during its meeting held on 6–7 December 2010, where the future of NBS was discussed in a workshop. Conclusions were integrated in a draft of the Expert Opinion document that was circulated by e-mail on 9 March 2011 to the membership of EUNENBS and to European Union Committee of Experts on Rare Diseases members from the Candidate and European Economic Area/European Free Trade Association countries inviting comments. This consultation ended on 6 April 2011. The preparation of the second draft, integrating the suggestions received, took place until 6 May 2011. Before the consensus meeting on 20 and 21 June 2011 in Luxembourg, the document was circulated for a second consultation, which took place from 11 to 27 May 2011, and amended considering the comments received. The Expert Opinion document was endorsed by the Boards of the International Society for Neonatal Screening and the European Society of Human Genetics in August and October 2011.Experiences from other countries have served as useful sources, although their applicability may need to be checked against information from EU countries and agreement needs to be sought with EUNENBS. This article presents the 70 Expert Opinions, resulting from the debate among the EUNENBS members with respect to the elements that are part of a system to evaluate the quality and ethical aspects of neonatal screening in the light of available literature, as well as the proposal for a decision matrix. We furthermore provide a brief discussion.     

Disturbed function of the blood–cerebrospinal fluid barrier aggravates neuro-inflammation

Multiple sclerosis (MS) is a chronic neuro-inflammatory disorder, which is marked by the invasion of the central nervous system by monocyte-derived macrophages and autoreactive T cells across the brain vasculature. Data from experimental animal models recently implied that the passage of leukocytes across the brain vasculature is preceded by their traversal across the blood–cerebrospinal fluid barrier (BCSFB) of the choroid plexus. The correlation between the presence of leukocytes in the CSF of patients suffering from MS and the number of inflammatory lesions as detected by magnetic resonance imaging suggests that inflammation at the choroid plexus contributes to the disease, although in a yet unknown fashion. We here provide first insights into the involvement of the choroid plexus in the onset and severity of the disease and in particular address the role of the tight junction protein claudin-3 (CLDN3) in this process. Detailed analysis of human post-mortem brain tissue revealed a selective loss of CLDN3 at the choroid plexus in MS patients compared to control tissues. Importantly, mice that lack CLDN3 have an impaired BCSFB and experience a more rapid onset and exacerbated clinical signs of experimental autoimmune encephalomyelitis, which coincides with enhanced levels of infiltrated leukocytes in their CSF. Together, this study highlights a profound role for the choroid plexus in the pathogenesis of multiple sclerosis, and implies that CLDN3 may be regarded as a crucial and novel determinant of BCSFB integrity.     

Blutungsneigung

Patients suffering from hemorrhagic disorders often present with only minimal bleeding during surgery or injuries. However, some patients have life-threatening bleeding. Simple screening tests can be used to find the cause of the bleeding: patient and family histories provide information on whether the bleeding tendency is hereditary or acquired. Clinical examination can reveal the bleeding type. Measurement of platelet count can be used to exclude thrombocytopenia. Coagulation tests, such as prothrombin time (PT, Quick) and activated partial thromboplastin time (aPTT) can supply initial information concerning deficiency states of coagulation factors. Bleeding time is often prolonged in patients suffering from von Willebrand disease, thrombocytopenia or thrombocytopathy. If—due to the results of these screening tests—further testing of particular coagulation factors or platelet function is needed, then patients should be referred to a centre specialized in blood coagulation.