Introduction to stem cells

Totipotent

Stem cells that can differentiate into all tissues, such as a fertilized egg.

Pluripotent

Stem cells capable of differentiating into cells from all three germ layers.

Multipotent

Stem cells that can self-renew and differentiate into a closely related family of cells.

Oligopotent

Stem cells that can differentiate into only closely related cell types, like myeloid and lymphoid cells.

Unipotent

Stem cells that can differentiate into only one cell type.

Embryonic Stem Cells (ESCs)

Stem cells derived from the inner cell mass of the blastocyst, considered the most potent.

Fetal Stem Cells

Stem cells obtained from terminated pregnancies, with limited potency and used in diseases like Batten disease.

Perinatal Stem Cells

Stem cells from amniotic fluid and fetal epithelial cells, possessing characteristics of mesenchymal stem cells.

Wharton Jelly

A source of mesenchymal stem cells found in the umbilical cord, rich in fibroblasts and macrophages.

Mesenchymal Stem Cells (MSCs)

Stromal cells with immunomodulatory characteristics, capable of differentiating into various cell types.

Embryonic Stem Cells (ESCs)

Cells derived from human blastocysts in 1988, capable of differentiating into various cell types, including retinal pigment epithelium.

Induced Pluripotent Stem Cells (iPSCs)

Stem cells derived from human somatic cells in 2006 by reprogramming, offering potential for regenerative therapies without ethical concerns.

Reprogramming

Process of opening chromatin to make it transcriptionally active, allowing the differentiation of stem cells into specific cell types.

iPSC-based Therapy

Utilizing iPSCs for personalized cell therapy, offering potential benefits but facing challenges like cost, time, and genetic mutations.

HLA Matching

Matching human leukocyte antigens (HLA) for allogeneic transplantation to reduce rejection risks in iPSC-based therapies.

CRISPR

Genome editing tool used to create universal donor cells by removing HLA molecules, enabling broader application of iPSC-based therapies.

Ethical Issues in Stem Cell Research

Debates surrounding the moral status of embryos, regulations, and public policy approaches to govern stem cell research.

Media Misrepresentation

Instances of exaggerated claims and unethical practices in stem cell therapies, highlighting the importance of ethical considerations and regulatory oversight.

Regulatory Science

Challenges in regulating advanced therapies like gene therapies and tissue engineering components to ensure safety and efficacy in clinical applications.

Unlicensed Therapies

Therapies administered without proper authorization or approval, often leading to potential risks and uncertainties.

Equipoise Problem

The ethical dilemma of whether a placebo-controlled trial is justifiable when uncertainty exists about the effectiveness and safety of a medical intervention.

Conflict of Interest

A situation where personal interests or relationships could unduly influence professional judgment or decision-making.

Informed Consent

Permission granted by a patient or participant after being informed of the risks, benefits, and alternatives of a medical intervention or clinical trial.

Stem Cell Niche

The microenvironment surrounding stem cells that regulates their behavior and function.

Niche Manipulation

Altering the surrounding environment of stem cells to influence their behavior, both in laboratory settings and within living organisms.

Cancer Stem Cell Niche

The specialized microenvironment that influences the behavior and characteristics of cancer stem cells.

Genetic Modification

Directly changing the genetic material of cells or organisms, including adding, correcting, or mutating genes.

Homologous Recombination

A genetic process where similar or identical DNA sequences exchange information, often used in gene editing and creating knockout models.

Lineage Tracing

A technique to track the developmental history of cells and their descendants within an organism, often using reporter genes for visualization.

Viral Vectors

Vectors that integrate into the host genome, such as retroviruses and lentiviruses, to remove viral structures and replace them with a transgene or gene of interest.

Genome Editing

The process of modifying an organism's DNA, often using molecular scissors like CRISPR, to make precise changes such as correcting abnormal genes or adding new genes.

CRISPR

A diverse tool for genome editing that induces double-stranded DNA breaks, leading to repair mechanisms like HDR (homology-directed repair) and NHEJ (non-homologous end joining).

Gene Therapy

Strategies that modify gene expression or correct abnormal genes, like gene addition or augmentation, to treat genetic conditions such as recessive dystrophic epidermolysis bullosa.

Base Editors

Tools for gene editing that do not require double-stranded breaks, offering higher efficiency, such as ABE (adenine base editor) and ADE (adenine base editor) for precise changes like converting cytosine to adenine.

Stem Cell Manufacturing

Scalable production of stem cells using CRISPR-edited autologous induced pluripotent stem cells (iPSCs) to enhance regenerative potential and long-lasting effects in treatments like epidermal grafts.

Haematopoiesis

The process of blood cell production in the bone marrow, involving different types of blood cells and the regulation of hematopoietic stem cells (HSCs) for maintaining blood cell balance.

Cord Blood Banking

Collection and storage of umbilical cord blood rich in hematopoietic stem cells for allogeneic use, providing advantages like better tolerance to HLA mismatches and less stringent match requirements in transplants.

Stem Cell Niche

Specialized environments supporting stem cell function, like the bone marrow niche, where factors like osteoblasts play a crucial role in regulating hematopoietic stem cells.

Hippocampal Stem Cell Neurogenesis

The production of new neurons by stem cells in the hippocampus, regulated by molecular mechanisms within the niche, to modulate brain functionality and differ from prenatal neurogenesis.

Adult Neurogenesis

The process of generating new neurons in the adult brain, particularly in regions like the hippocampus, sub ventricular zone (SVZ), and sub granular zone of dentate gyrus (DG).

Neural Stem Cells (NSC)

Cells that have the capacity to proliferate, migrate, and differentiate into neurons in the adult brain, expressing markers like GFAP and Sox2.

Hippocampus Niche

A specialized microenvironment in the hippocampus that supports neurogenesis, characterized by factors like vascularization, astrocytes, and neural stem cells sheeting the blood vessels.

Osteoblasts

Cells responsible for bone formation by depositing mineralized matrix, crucial for maintaining bone integrity and structure.

Osteoclasts

Multinucleated cells involved in bone resorption, breaking down bone tissue through acid demineralization, essential for bone remodeling and calcium homeostasis.

Mesenchymal Stem Cells (MSCs)

Stem cells that can differentiate into various mesenchymal cell types, including osteoblasts, chondrocytes, and adipocytes, crucial for bone repair and regeneration.

Stem Cell Niche

The specific microenvironment that supports and regulates stem cell function, providing cues for self-renewal, differentiation, and maintenance of stemness.

Chondrogenesis

The process of cartilage formation, driven by factors like BMPs and GDF5, essential for endochondral ossification and joint development.

Epidermal Stem Cells

Cells located in the skin niche responsible for skin renewal and repair, crucial for maintaining skin homeostasis and integrity.

Collagen

The most abundant protein in the skin, providing structural support and tensile strength, with different types like collagen 1 and collagen 3 playing key roles in skin structure and wound healing.

Collagen Ratios

Changes in the proportions of collagen in scars, leading to different types like hypertrophic or keloid scars.

Proteoglycans and GAGs

Long linear polysaccharide chains in the skin composed of specific disaccharide units, forming a complex network.

HA Synthesis

The process of producing hyaluronic acid in the skin, with proposed methods for its breakdown.

Skin Ageing

The gradual degradation of the skin over time, leading to changes like wrinkles and reduced collagen and elastin production.

Mechanotransduction

The process by which cells sense mechanical cues and respond accordingly, affecting stem cell behavior and tissue engineering.

Elastic Modulus

A measure of the stiffness of a material, influencing how cells sense and respond to mechanical forces in their environment.

Tensegrity Structures

Cellular structures where components are connected by tensile elements, influencing cell shape, behavior, and differentiation.

Stem Cell Differentiation

The process by which stem cells commit to specific lineages, influenced by mechanical cues like cell shape and cytoskeletal tension.

Matrix Stiffness Effects

The impact of the stiffness of the extracellular matrix on cell differentiation and gene expression, affecting stem cell behavior.

YAP/TAZ Signaling

Cellular pathways regulated by ECM stiffness and cytoskeletal tension, influencing stem cell mechanotransduction and differentiation.