A Preview of Selected Articles

death of the upper and lower motor neurons that control voluntary muscles, subsequent muscle deterioration, and ultimately death. Currently approved drug treatments offer only modest benefits [1, 2], and so, many have looked to stem cells as novel therapeutic agents for the treatment of ALS and related neurological disorders. The intraspinal transplantation of neural stem/progenitor cells (NSCs/NPCs) as a treatment strategy for ALS aims to reduce local astrogliosis and microgliosis, modulate immune responses, and provide neurotrophic support through the secretion of factors such as brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor (GDNF), and vascular endothelial growth factor [3]. While encouraging results have been reported, current research aims in this field include the search for a safe and effective stem cell source, the assessment of cell-engineering approaches that may potentiate therapeutic outcomes, and the appraisal of multiple stem cell administrations to target areas in the spinal cord and the brain. In our first Featured Article published in Stem Cells Translational Medicine this month, Mazzini et al. report on a successful phase I trial that assessed the feasibility and safety of transplanting non-immortalized fetal human NSCs into the spinal cord of ALS patients, reporting evidence of therapeutic efficacy [4]. In a Related Article published in Stem Cells, Thomsen et al. demonstrated that transplantation of GDNF-expressing NPCs into the motor cortex protected upper and lower motor neurons, delayed disease pathology, and extended survival after transplantation into a rat model of ALS, while also reporting encouraging findings in cynomolgus macaques [5]. The decellularization of organs or tissues leaves behind an extracellular matrix (ECM) scaffold with a unique composition and architecture that can be repopulated by autologous somatic and stem cell populations to generate transplantable graft tissues. Said tissues have the potential to overcome difficulties encountered in allogeneic transplantation approaches, which include immune rejection, pronounced donor shortages, and problems related to organ transport and storage [6]. Current research employing decellularized ECM scaffolds includes the generation of kidney, liver, lung, and heart tissues, but also extends to the generation of corneal, blood vessel, nerve conduit, cartilage, and tendon constructs to name but a few [7]. However, fascinating studies have also used these decellularized scaffolds to ascertain the essential role of the various components of the ECM in the regulation of various types of stem cells [8], including muscle stem cells. In our second Featured Article published in Stem Cells Translational Medicine this month, Lu et al. establish that a decellularized allogenic tendon scaffold combined with autologous bone marrow-derived mesenchymal stem cells (MSCs) significantly improves anterior cruciate ligament (ACL) reconstruction in a rabbit model when compared with free tendon allografts [9]. In a Related Article published in Stem Cells, Zhang et al. demonstrated how three-dimensional decellularized constructs derived from arsenic-exposed muscles displayed increased fibrogenic conversion and decreased myogenicity after seeding with naïve human muscle stem cells when compared with cells seeded into control constructs in a study that offers insight into the influence of the native myomatrix on stem cell behavior [10].