Developing Educational Resources to Advance Umbilical Cord Blood Banking and Research: A Canadian Perspective.

In 2013 Canadian Blood Services (CBS) launched the National Public Cord Blood Bank (NPCBB), a program to collect, process, test, and store cord blood units donated for use in transplantation. A key component of the creation of the NPCBB is the establishment of a program that enables cord blood not suitable for banking or transplantation to be used for biomedical research purposes. Along with the development of processes and policies to manage the NPCBB and the cord blood research program, CBS-in collaboration with researchers from the Stem Cell Network-have also developed educational tools to provide relevant information for target audiences to aid implementation and operation. We describe here one of these tools, the REB Primer on Research and Cord Blood Donation (the Primer), which highlights key ethical and legal considerations and identifies Canadian documents that are relevant to the use of cord blood in biomedical research. The Primer also introduces the NPCBB and describes the systems CBS is implementing to address ethical issues. The Primer is intended to assist research ethics boards in evaluating the ethical acceptability of research protocols, to facilitate harmonized decision-making by providing a common reference, and to highlight the role of research ethics boards in governance frameworks. With the Primer we hope to illustrate how the development of such educational tools can facilitate the ethical implementation and governance of programs related to stem cell research in Canada and abroad.

En 2013, la Société canadienne du sang (SCS) a lancé la Banque publique nationale de sang de cordon ombilical (BPNSCO) : un programme de prélèvement, de traitement, d'analyse et d'entreposage d'unités de sang de cordon ombilical ayant fait l'objet d'un don pour une utilisation dans le cadre de greffes. La mise sur pied d'un programme permettant l'utilisation, aux fins de la recherche biomédicale, du sang de cordon ombilical ne pouvant être mis en banque ni être utilisé pour des greffes constitue une composante clé de la création de la BPNSCO. Conjointement avec l'élaboration de processus et de politiques permettant la gestion de la BPNSCO et du programme de recherche sur le sang de cordon ombilical, la SCS (en collaboration avec les chercheurs du Réseau de cellules souches) ont également conçu des outils pédagogiques permettant l'offre de renseignements pertinents aux populations visées, de façon à faciliter la mise en œuvre et la gestion des activités. Nous décrivons ici l'un de ces outils : le REB Primer on Research and Cord Blood Donation (le « guide ¼). Ce « guide ¼ souligne les enjeux éthiques et légaux clés, et identifie les documents canadiens pertinents en ce qui concerne l'utilisation de sang de cordon ombilical aux fins de la recherche biomédicale. Ce « guide ¼ présente également la BPNSCO et décrit les systèmes qui sont mis en œuvre par la SCS pour répondre aux questions éthiques. Il a pour but d'aider les conseils d'éthique de la recherche à évaluer l'acceptabilité éthique des protocoles de recherche, de faciliter l'harmonisation des processus décisionnels en offrant un cadre de référence commun et de souligner le rôle des conseils d'éthique de la recherche dans les cadres de gouvernance. Grâce à ce « guide ¼, nous espérons illustrer la façon dont l'élaboration de tels outils pédagogiques peut faciliter la mise en œuvre et la gestion éthiques de programmes associés à la recherche sur les cellules souches au Canada et à l'étranger.

Platelet utilization: a Canadian Blood Services research and development symposium.

Considerable progress has been made in recent years in understanding platelet biology and in strengthening the clinical evidence base around platelet transfusion thresholds and appropriate platelet dosing. Platelet alloimmunization rates have also declined. Nevertheless, controversies and uncertainties remain that are relevant to how these products can best be used for the benefit of platelet transfusion recipients. Platelets are unique among the blood products directly derived from whole blood or apheresis donations in requiring storage, with shaking, at ambient temperature. Storage is accordingly constrained between the need to limit the growth of any microbes in the product and the need to minimize losses in platelet function associated with storage. Proteomic and genomic approaches are being applied to the platelet storage lesion. Platelet inventory management is made challenging by these constraints. Although bacterial screening has enhanced the safety of platelet transfusions, pathogen reduction technology may offer further benefits. Continuing clinical investigations are warranted to understand the value of transfusing platelets prophylactically or only in response to bleeding in different patient groups and how best to manage the most grievously injured trauma patients. Patients refractory to platelet transfusions also require expert clinical management. The engineering of platelet substitute products is an active area of research, but considerable hurdles remain before any clinical uses may be contemplated. Roles for platelets in biological areas distinct from hemostasis are also emerging. Platelet utilization is variably affected by all of the above factors, by demographic changes, by new medications, and by new patient care approaches.

MyoD- and nerve-dependent maintenance of MyoD expression in mature muscle fibres acts through the DRR/PRR element.

BACKGROUND: MyoD is a transcription factor implicated in the regulation of adult muscle gene expression. Distinguishing the expression of MyoD in satellite myoblasts and muscle fibres has proved difficult in vivo leading to controversy over the significance of MyoD expression within adult innervated muscle fibres. Here we employ the MD6.0-lacZ transgenic mouse, in which the 6 kb proximal enhancer/promoter (DRR/PRR) of MyoD drives lacZ, to show that MyoD is present and transcriptionally active in many adult muscle fibres. RESULTS: In culture, MD6.0-lacZ expresses in myotubes but not myogenic cells, unlike endogenous MyoD. Reporter expression in vivo is in muscle fibre nuclei and is reduced in MyoD null mice. The MD6.0-lacZ reporter is down-regulated both in adult muscle fibres by denervation or muscle disuse and in cultured myotubes by inhibition of activity. Activity induces and represses MyoD through the DRR and PRR, respectively. During the postnatal period, accumulation of beta-galactosidase correlates with maturation of innervation. Strikingly, endogenous MyoD expression is up-regulated in fibres by complete denervation, arguing for a separate activity-dependent suppression of MyoD requiring regulatory elements outside the DRR/PRR. CONCLUSION: The data show that MyoD regulation is more complex than previously supposed. Two factors, MyoD protein itself and fibre activity are required for essentially all expression of the 6 kb proximal enhancer/promoter (DRR/PRR) of MyoD in adult fibres. We propose that modulation of MyoD positive feedback by electrical activity determines the set point of MyoD expression in innervated fibres through the DRR/PRR element.

Distinct roles for Pax7 and Pax3 in adult regenerative myogenesis.

We assessed viable Pax7(-/-) mice in 129Sv/J background and observed reduced growth and marked muscle wasting together with a complete absence of functional satellite cells. Acute injury resulted in an extreme deficit in muscle regeneration. However, a small number of regenerated myofibers were detected, suggesting the presence of residual myogenic cells in Pax7-deficient muscle. Rare Pax3(+)/MyoD+ myoblasts were recovered from Pax7(-/-) muscle homogenates and cultures of myofiber bundles but not from single myofibers free of interstitial tissues. Finally, we identified Pax3+ cells in the muscle interstitial environment and demonstrated that they coexpressed MyoD during regeneration. Sublaminar satellite cells in hind limb muscle did not express detectable levels of Pax3 protein or messenger RNA. Therefore, we conclude that interstitial Pax3+ cells represent a novel myogenic population that is distinct from the sublaminar satellite cell lineage and that Pax7 is essential for the formation of functional myogenic progenitors from sublaminar satellite cells.

Cellular and molecular regulation of muscle regeneration.

Under normal circumstances, mammalian adult skeletal muscle is a stable tissue with very little turnover of nuclei. However, upon injury, skeletal muscle has the remarkable ability to initiate a rapid and extensive repair process preventing the loss of muscle mass. Skeletal muscle repair is a highly synchronized process involving the activation of various cellular responses. The initial phase of muscle repair is characterized by necrosis of the damaged tissue and activation of an inflammatory response. This phase is rapidly followed by activation of myogenic cells to proliferate, differentiate, and fuse leading to new myofiber formation and reconstitution of a functional contractile apparatus. Activation of adult muscle satellite cells is a key element in this process. Muscle satellite cell activation resembles embryonic myogenesis in several ways including the de novo induction of the myogenic regulatory factors. Signaling factors released during the regenerating process have been identified, but their functions remain to be fully defined. In addition, recent evidence supports the possible contribution of adult stem cells in the muscle regeneration process. In particular, bone marrow-derived and muscle-derived stem cells contribute to new myofiber formation and to the satellite cell pool after injury.

Aging-related satellite cell differentiation defect occurs prematurely after Ski-induced muscle hypertrophy.

To investigate the cause of skeletal muscle weakening during aging we examined the sequence of cellular changes in murine muscles. Satellite cells isolated from single muscle fibers terminally differentiate progressively less well with increasing age of donor. This change is detected before decline in satellite cell numbers and all histological changes examined here. In MSVski transgenic mice, which show type IIb fiber hypertrophy, initial muscle weakness is followed by muscle degeneration in the first year of life. This degeneration is accompanied by a spectrum of changes typical of normal muscle aging and a more marked decline in satellite cell differentiation efficiency. On a myoD-null genetic background, in which satellite cell differentiation is defective, the MSVski muscle phenotype is aggravated. This suggests that, on a wild-type genetic background, satellite cells are capable of repairing MSVski fibers and preserving muscle integrity in early life. We propose that decline in myogenic cell differentiation efficiency is an early event in aging-related loss of muscle function, both in normal aging and in some late-onset muscle degenerative conditions.