Markers of Regenerative Processes in Patients with Bipolar Disorder: A Case-control Study

Multipotent/pluripotent stem cell populations in stromal tissues and peripheral blood: exploring diversity, potential, and therapeutic applications

The concept of "stemness" incorporates the molecular mechanisms that regulate the unlimited self-regenerative potential typical of undifferentiated primitive cells. These cells possess the unique ability to navigate the cell cycle, transitioning in and out of the quiescent G0 phase, and hold the capacity to generate diverse cell phenotypes. Stem cells, as undifferentiated precursors endow with extraordinary regenerative capabilities, exhibit a heterogeneous and tissue-specific distribution throughout the human body. The identification and characterization of distinct stem cell populations across various tissues have revolutionized our understanding of tissue homeostasis and regeneration. From the hematopoietic to the nervous and musculoskeletal systems, the presence of tissue-specific stem cells underlines the complex adaptability of multicellular organisms. Recent investigations have revealed a diverse cohort of non-hematopoietic stem cells (non-HSC), primarily within bone marrow and other stromal tissue, alongside established hematopoietic stem cells (HSC). Among these non-HSC, a rare subset exhibits pluripotent characteristics. In vitro and in vivo studies have demonstrated the remarkable differentiation potential of these putative stem cells, known by various names including multipotent adult progenitor cells (MAPC), marrow-isolated adult multilineage inducible cells (MIAMI), small blood stem cells (SBSC), very small embryonic-like stem cells (VSELs), and multilineage differentiating stress enduring cells (MUSE). The diverse nomenclatures assigned to these primitive stem cell populations may arise from different origins or varied experimental methodologies. This review aims to present a comprehensive comparison of various subpopulations of multipotent/pluripotent stem cells derived from stromal tissues. By analysing isolation techniques and surface marker expression associated with these populations, we aim to delineate the similarities and distinctions among stromal tissue-derived stem cells. Understanding the nuances of these tissue-specific stem cells is critical for unlocking their therapeutic potential and advancing regenerative medicine. The future of stem cells research should prioritize the standardization of methodologies and collaborative investigations in shared laboratory environments. This approach could mitigate variability in research outcomes and foster scientific partnerships to fully exploit the therapeutic potential of pluripotent stem cells.

Dysregulation of complement system in neuropsychiatric disorders: A mini review

Complement system is one of the most important defense mechanisms of the innate immune system. In addition to their roles in immune regulation, complement proteins are also involved in neurodevelopment and adult brain plasticity. Complement dysregulation has been shown in neurodevelopmental disorders including schizophrenia and autism spectrum disorder as well as in mood disorders. A number of clinical as well as genetic studies suggest the role of complement proteins in the cortical thinning and excessive synaptic pruning frequently associated with schizophrenia. The changes in complement proteins are also associated with the pathophysiology of autism spectrum disorder, major depressive disorder and bipolar disorder, but warrant further research. In addition, rodent models suggest a strong case for complement system in anxiety-like behavior. In this article, we review the recent findings on the role of complement system in neuropsychiatric disorders. The possible uses for future complement targeted therapies are also discussed.

Psychopathology and Stem Cell Mobilization in Ultra-High Risk of Psychosis and First-Episode Psychosis Patients

Although regenerative and inflammatory processes are involved in the etiopathogenesis of many psychiatric disorders, their roles are poorly understood. We investigate the potential role of stem cells (SC) and factors influencing the trafficking thereof, such as complement cascade (CC) components, phospholipid substrates, and chemokines, in the etiology of schizophrenia. We measured sphingosine-1-phosphate (S1P), stromal-derived factor 1 (SDF-1), and CC cleavage fragments (C3a, C5a, and C5b-C9; also known as the membrane attack complex) in the peripheral blood of 49 unrelated patients: 9 patients with ultra-high risk of psychosis (UHR), 22 patients with first-episode psychosis (FEP), and 18 healthy controls (HC). When compared with the HC group, the UHR and FEP groups had higher levels of C3a. We found no significant differences in hematopoietic SC, very small embryonic-like stem cell (VSEL), C5a, S1P, or SDF-1 levels in the UHR and FEP groups. However, among FEP patients, there was a significant positive correlation between VSELs (CD133+) and negative symptoms. These preliminary findings support the role of the immune system and regenerative processes in the etiology of schizophrenia. To establish the relevance of SC and other factors affecting the trafficking thereof as potential biomarkers of schizophrenia, more studies on larger groups of individuals from across the disease spectrum are needed.