Cardiac and skeletal stem cells play important roles in tissue homeostasis and regeneration. Cardiac stem cells are found in the adult heart and can generate new cardiomyocytes and blood vessels to repair damage. Skeletal stem cells in developing bone give rise to chondrocytes and osteoblasts during endochondral bone formation and help maintain the skeleton. While stem cells show promise for regenerative therapies, more research is needed to fully understand their functions in vivo.

1. CARDIAC AND
SKELETAL STEM CELLS
KATTULA JYSOTHSNA

2. STEM
CELLS:
• A stem cell is a cell with
the potential to form many
of the different cell types
found in the body. When
stem cells divide, they can
form more stem cells or
other cells that perform
specialized functions.

4. Cardiac stem cells:
Introduction:
• In this industrialized world where we are living, Heart disease is the major cause of
death
• Replacement of lost cardiomyocytes must continue in order to maintain heart
function.
• An uncompensated decrease in the number of healthy and completely functional
cardiomyocytes is what causes cardiac failure.
• Heart transplantation is still the sole treatment option for severe heart failure,
despite the fact that current pharmaceutical medications reduce the symptoms of
cardiac disease.
• Cell-based therapies that use cardiac stem cells (CSCs) represent a promising new
strategy for replacing damaged tissue and regaining cardiac function.
• As, there is a need for new therapeutic approaches.

5.  Function:
• CSCs are found in the adult heart and control the homeostasis of the myocardium and its
ability to heal after injury by generating fresh cardiomyocytes and vascular tissues.
• C-kit-positive CSCs : Cells that regulate the growth and maturation of the prenatal organ and
generate myocytes upon transplantation, that are produced highly in embryonic and fetal
hearts.
• Furthermore, in a model of myocardial infarction, CDCs (cardiosphere-derived cells) from a
neonatal heart contain a significant proportion of undifferentiated cells that express c-kit or
Sca-1(stem cell antigen-1) and have potent regeneration abilities.
• The cardiac interstitium contains specialized microdomains known as stem cell niches where
CSCs and early lineage-committed cells are nestled.
• The transcription factors GATA-4, Nkx2.5, or MEF2c, as well as c-kit, are expressed by the
myocyte-specific progenitors in the niches.

6. • When c-kit-positive CSCs are transplanted into a damaged heart, a large pool of
functionally competent cardiomyocytes, resistance arterioles, and capillary profiles
are produced, partially healing the infarcted myocardial, shrinking the infarct, and
attenuating ventricular remodelling.
• There are significant clinical and experimental evidences demonstrating that the heart
can heal itself, although to a limited extent. The repair process requires the activity of
cardiac stem cells (CSCs) residing in the adult myocardium.
• Advances in the understanding of CSC biology indicate that cell-autonomous and
environmental changes in the redox status also control CSC growth, survival,
differentiation and, ultimately, regenerative potential.
• Therefore, developing methods to alter redox signalling in the heart has significant
therapeutic implications.
• A key objective of cardiac stem cell therapy is to inject a sufficient number of cells
into the heart at the location of damage or infarction to maximise function recovery.
• Stem cells are delivered directly into the coronary arteries using the transvascular
route.
• Direct Injection Into the Ventricular Wall: When total blockage makes a transvascular
technique impractical.

7. Skeletal
stem cells:
• Skeletal stem cells (SSCs), a type of somatic stem cells
dedicated to bones, are considered to play important roles in
development, homeostasis, and regeneration of bone tissues.
• They are generally defined as self-renewing cells with the
“trilineage” potential to differentiate into chondrocytes,
osteoblasts, marrow stromal cells, or adipocytes in vitro.
However, the in vivo identity of SSCs remains largely elusive.
• A variety of SSCs are generated during the course of bone
development. Formation of mesenchymal condensations within
the limb bud is the initial step for endochondral bone
development, by which most of bones are formed.
• These condensations of undifferentiated mesenchymal cells
produce chondrocytes, which through cycles of cell
proliferation and differentiation shape and enlarge the cartilage
template.

8. • SSCs with robust transplantability can be isolated from developing growth plates
using a panel of cell surface markers and cell transplantation experiments, both in
humans and mice.
• Human SSCs are defined as PDPN+CD146−CD73+CD164+ non-hematopoietic
mesenchymal cells, which are isolated by mechanical and collagenase digestion from
the fetal femoral head cartilage that includes proliferating, pre-hypertrophic, and
hypertrophic zone
• Over the past 50 years, bone marrow has yielded mesenchymal stem cells (MSCs),
also known as SSCs, which have been extensively used in regenerative medicine.
Particularly among CD146+ perisinusoidal stromal cells in human bone marrow,
these cells are localised around bone marrow sinusoids preferentially. These
perisinusoidal stromal cells have a distinctive reticular cell shape and highly active
alkaline phosphatase. However, there are still questions about the in vivo identity of
SSCs or MSCs, mainly because there aren't any genetic techniques or SSC-specific
markers that can accurately identify these cells in vivo.

9. Resources :
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC420
8604/
• https://pubmed.ncbi.nlm.nih.gov/26269526/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC725
5932/#:~:text=Skeletal%20stem%20cells%20(SSCs
)%20are,about%20their%20in%20vivo%20identity.