HMM103 – Stem Cells and Therapy (Vocabulary Flashcards)

Vocabulary flashcards summarizing key terms, concepts, types, processes, and challenges related to stem cells and their therapeutic applications.

Stem Cell

An undifferentiated cell capable of self-renewal and differentiation into specialized cell types.

Cell Differentiation

Process by which unspecialized cells become specialized, permanently switching off genes not required for their specific function.

Self-Renewal

Ability of a stem cell to divide indefinitely while maintaining an undifferentiated state.

Potency

A stem cell’s potential to differentiate into different cell types.

Totipotent Cell

Stem cell able to form all embryonic and extra-embryonic tissues; found only in the zygote and first few embryonic divisions (1–3 days).

Pluripotent Cell

Stem cell that can give rise to any adult body cell type but not extra-embryonic tissues; resides in the inner cell mass of the blastocyst (5–14 days).

Multipotent Cell

Stem cell that can differentiate into multiple, closely related lineages (e.g., hematopoietic stem cells).

Oligopotent Cell

Stem cell restricted to a few cell types within a lineage (e.g., myeloid or lymphoid progenitors).

Unipotent Cell

Stem cell capable of producing only one cell type (e.g., epidermal stem cells).

Terminally Differentiated Cell

Fully specialized cell with no capacity to self-renew or further differentiate.

Embryonic Stem Cell (ESC)

Pluripotent/totipotent cells isolated from the inner cell mass of a blastocyst that can proliferate indefinitely in culture.

Induced Pluripotent Stem Cell (iPSC)

Adult somatic cell genetically reprogrammed (e.g., via OCT4, SOX2, KLF4, c-MYC) to an embryonic-like pluripotent state.

Adult Stem Cell

Lineage-restricted stem cell found in mature tissues; usually multipotent or oligopotent.

Mesenchymal Stem Cell (MSC)

Multipotent stromal cell, often from bone marrow, that can generate bone, cartilage, fat, muscle, and tendon cells.

Hematopoietic Stem Cell (HSC)

Multipotent stem cell that replenishes all blood and immune cells; sourced from bone marrow, cord blood, or peripheral blood.

Neural Stem Cell (NSC)

Multipotent stem cell that produces neurons, astrocytes, and oligodendrocytes; found in brain tissue or derived from ESCs.

Symmetric Division

Stem-cell division yielding two identical stem cells, expanding the stem cell pool.

Asymmetric Division

Stem-cell division producing one stem cell and one differentiating daughter cell, maintaining stem cell numbers.

Blastocyst

Early embryonic structure (~5 days) containing an outer trophoblast and inner cell mass (source of ESCs).

Zygote

Fertilized egg; first totipotent cell of an organism.

Morula

Solid ball of cells formed after zygote cleavage; still totipotent.

Gastrula

Embryonic stage where three germ layers (ectoderm, mesoderm, endoderm) are established.

Ectoderm

Outer germ layer that forms nervous system, epidermis, and related structures.

Mesoderm

Middle germ layer that forms muscle, bone, blood, and connective tissue.

Endoderm

Inner germ layer that forms gut lining, liver, pancreas, and respiratory tract.

Stem Cell Niche

Microenvironment of surrounding cells and signals that regulate stem cell maintenance and behavior.

Autologous Stem Cell Transplantation

Therapy using a patient’s own stem cells; lowers risk of immune rejection and speeds engraftment.

Allogeneic Stem Cell Transplantation

Therapy using stem cells from a donor; higher rejection risk but can provide healthy, disease-free cells.

Cell-Based Therapy

Treatment in which living cells (often stem cells) are introduced to repair or replace damaged tissues.

Regenerative Medicine

Field focused on replacing, engineering, or regenerating human cells, tissues, or organs to restore function.

Directed Differentiation

Laboratory process of adding specific growth factors/cytokines to guide stem cells into a desired lineage.

Gene-Modified Stem Cell Therapy

Approach where stem cells are genetically engineered with a therapeutic gene before transplantation.

Ernest McCulloch and James Till

Researchers who discovered stem cells in the early 1960s through bone marrow experiments.

1958 Bone Marrow Transplant

First successful stem-cell-based therapy treating radiation accident victims with donor marrow.

Self-Renewal Factors

Extrinsic or intrinsic signals (e.g., LIF, Wnt) that maintain stem cell proliferation without differentiation.

De-Differentiation Factors

Genes (e.g., OCT4, SOX2) used to revert specialized cells back to a pluripotent state in iPSC creation.

Stem Cell Therapy Challenges

Issues including ethical concerns, tumorigenicity, immune rejection, limited knowledge, cost, and delivery efficiency.

Tumorigenicity

Potential of undifferentiated stem cells to form teratomas or tumors after transplantation.

Immune Rejection

Host immune response that attacks transplanted cells perceived as foreign.

Ethical Concerns (ESC)

Moral objections related to destroying embryos to derive embryonic stem cells.

Stem Cell Potency Hierarchy

Ordered levels of differentiation potential: totipotent → pluripotent → multipotent → oligopotent → unipotent.

Growth Factors (e.g., FGF, BMP, Wnt)

Signaling molecules that influence stem cell self-renewal and lineage commitment.

Stem Cell Therapy Applications

Clinically targeted diseases such as blood cancers, Crohn’s disease, neurodegenerative disorders, cardiac repair, and genetic defects.

Skin Graft Tissue Engineering

Use of skin stem cells to grow replacement epidermal tissue for burn or wound treatment.

iPSC Disease-in-a-Dish

Modeling patient-specific diseases by differentiating their iPSCs into affected cell types for study or drug screening.

Stem Cell Engraftment

Process by which transplanted stem cells lodge and begin producing functional progeny in the host tissue.