Restoring the Degenerating Brain: Mesenchymal and Neural Stem Cells in Neurotherapeutics

Neurodegenerative and neuroinflammatory disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS) represent complex, multifactorial conditions as well as traumatic brain injury (TBI) and spinal cord injury (SCI) involving neuroinflammation, progressive neuronal loss, synaptic dysfunction, and blood-brain barrier (BBB) disruption. Despite advances in symptomatic management, current therapies only modestly delay disease progression. Stem cell-based therapies offer a promising multi-target approach by addressing key pathological mechanisms, including inflammation, neuronal degeneration, and impaired regeneration. Two major stem cell types, mesenchymal stem cells (MSCs) and neural stem/ progenitor cells (NSPCs), have shown therapeutic potential in both preclinical and clinical studies. MSCs, derived from bone marrow, adipose tissue, and umbilical cord, act primarily via paracrine signaling, secreting trophic and immunomodulatory factors such as BDNF, VEGF, and NGF to promote repair and modulate the neuroinflammatory milieu. In contrast, NSPCs contribute to neurogenesis and gliogenesis, with potential for direct cell replacement and circuit integration, particularly in diseases involving specific neuronal loss. However, their therapeutic use must consider significant regional heterogeneity; for example, cortical and hippocampal NSPCs differ in developmental origin, fate potential, and response to environmental cues. Similarly, MSCs from different tissues exhibit distinct immunomodulatory and differentiation capacities. BBB permeability remains a critical barrier to effective CNS delivery of systemically administered therapies. Yet, stem cells may cross or modulate the BBB or be directly transplanted into the CNS. Current clinical trials are evaluating stem cell-based therapies in neurodegenerative disease and CNS injury, with early results showing safety and potential functional benefits. Nonetheless, variability in cell source, delivery, and survival, along with the need for standardized manufacturing and dosing protocols, continue to limit clinical translation. This review highlights the therapeutic promise and translational hurdles of MSCs and NSPCs as multi-target strategies to address the cellular and molecular complexity of CNS disorders can cope and adapt to life in the city environment. The welfare state nurtures the ordinary people who make up the majority of the Swedish population. The model satisfies wayward people, such as homeless individuals and patients with disabilities.