Muscle Interstitial Cells: A Brief Field Guide to Non-satellite Cell Populations in Skeletal Muscle

Skeletal muscle regeneration is mainly enabled by a population of adult stem cells known as satellite cells. Satellite cells have been shown to be indispensable for adult skeletal muscle repair and regeneration. In the last two decades, other stem/progenitor cell populations resident in the skeletal muscle interstitium have been identified as "collaborators" of satellite cells during regeneration. They also appear to have a key role in replacing skeletal muscle with adipose, fibrous, or bone tissue in pathological conditions. Here, we review the role and known functions of these different interstitial skeletal muscle cell types and discuss their role in skeletal muscle tissue homeostasis, regeneration, and disease, including their therapeutic potential for cell transplantation protocols

Canid Paleoichnology: Taxonomic Review and Producers of Canipeda from the Late Pleistocene of Argentina

This contribution reviews the worldwide record of canid and canid-like (creodont and hyaenid) fossil footprints, the taxonomy of this type of footprints, and reports a new record of canid footprints from the late Pleistocene Pehuen Co site of southern Buenos Aires province, Argentina. On the basis of the comparison of proposed ichnogenera and features of modern canid and felid footprints, a set of ichnogeneric and ichnospecific taxobases are proposed. The ichnotaxonomic review includes Bestiopeda Vialov, 1965; Canipeda Panin and Avram, 1962; Felipeda Panin and Avram, 1962; Pehuencoichnum Aramayo and Manera de Bianco, 1987b; Creodontipus Santamaría et al. 1989–1990; Tetrastoibopus Sarjeant and Langston, 1994; and Quiritipes Sarjeant et al. 2002. A key to discriminate these ichnotaxa is also proposed and the diagnosis of Canipeda emended. The new findings of canid footprints from Pehuen Co are indistinguishable from Pehuencoichnum gracilis Aramayo and Manera de Bianco, 1987b, and this ichnospecies is synonymized under Canipeda gracilis (Vialov, 1965). An emended diagnosis for C. gracilis is proposed. The most likely producer of C. gracilis from Pehuen Co is a medium-sized fox similar to the extant representatives of Lycalopex.Fil: Melchor, Ricardo Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Feola, Silverio Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; ArgentinaFil: Manera, Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Geológico del Sur. Universidad Nacional del Sur. Departamento de Geología. Instituto Geológico del Sur; Argentin

Pericytes in Muscular Dystrophies

The muscular dystrophies are an heterogeneous group of inherited myopathies characterised by the progressive wasting of skeletal muscle tissue. Pericytes have been shown to make muscle in vitro and to contribute to skeletal muscle regeneration in several animal models, although recent data has shown this to be controversial. In fact, some pericyte subpopulations have been shown to contribute to fibrosis and adipose deposition in muscle. In this chapter, we explore the identity and the multifaceted role of pericytes in dystrophic muscle, potential therapeutic applications and the current need to overcome the hurdles of characterisation (both to identify pericyte subpopulations and track cell fate), to prevent deleterious differentiation towards myogenic-inhibiting subpopulations, and to improve cell proliferation and engraftment efficacy