​Human or animal stem cells?

Human or animal stem cells?

July 23, 2024

Healthcaretoday, AIMM, stem cells, healthspan, Association of Integrative Medicine Malaysia, Integrative Medicine, Stem cell research, autologous transplant, allogenic transplant, xenogenic transplant, stem cell aging, medical ethics, embryonic stem cells, somatic stem cells, bone marrow transplant, medical advancements, genetic diseases, cell therapy,

At the 5th International Integrative Medicine Conference 2024, themed "Healthspan - The Science and Art of Wellbeing," the Association of Integrative Medicine Malaysia (AIMM) brought together experts to discuss cutting-edge developments in integrative medicine. Among the notable speakers was Dr Jason A. Penaranda from the Philippines, who delivered an insightful lecture on "Comparison of autologous, allogenic, and xenogenic stem cell transplants."

Dr Penaranda's presentation delved into the intricacies of stem cell transplantation, highlighting the benefits and drawbacks of each type—autologous (autogenic), allogenic, and xenogenic. His talk underscored the potential of these therapies to revolutionize regenerative medicine, provided that ethical considerations and practical challenges are addressed.

Understanding stem cells
Before diving into the types of stem cell transplants, Dr Penaranda laid the groundwork by explaining what stem cells are and their significance in medicine. Stem cells are remarkable for their ability to self-replicate and differentiate into various cell types, making them essential for growth, repair, and regeneration.

There are two primary types of stem cells: embryonic and somatic.
Embryonic stem cells:
Advantages: Pluripotent, meaning they can differentiate into any cell type. They are easily grown and multiplied in the lab.
Disadvantages: High risk of developing teratomas and teratocarcinomas, and significant ethical concerns.

Somatic stem cells (MSC):
Advantages: Harvested from adult human tissues such as bone marrow and adipose tissue. They have a higher chance of developing into the cell type of the target organ and pose negligible risk for tumors.

Disadvantages: Harvesting is invasive and the self-renewal rate is lower compared to embryonic stem cells.

Types of stem cell transplants
Autologous (autogenic) stem cell transplants
Advantages:

High safety profile.
Very low risk of infection transfer.
No ethical concerns since the cells are from the patient's own body.

Disadvantages:

Invasive collection process.
Time-consuming to harvest, process, and expand.

As we age, the number of stem cells in our bone marrow decreases. Newborns have 1 stem cell per 10,000 marrow cells, teens have 1 per 100,000, adults at 30 have 1 per 250,000, and at 50, there is only 1 per 400,000. This decline impacts the body's ability to repair and regenerate tissues effectively.

Stem cell aging framework
Dr Penaranda outlined how different types of stem cells age and the implications for their use in therapies:

Neural stem cell aging: Experiences asynchronous depletion, lengthening quiescence, decreased proliferation, imbalanced self-renewal, decreased neuronal fate commitment, increased inflammation, altered proteostasis, and epigenetic loss of DNA methylation.
Hematopoietic stem cell aging: Characterized by imbalanced immune response, declined regeneration, myeloid-biased differentiation, cytoskeletal polarity shifts, epigenetic drifts, and clonal selection.
Intestinal stem cell aging: Results in diminished regeneration, decreased crypt numbers, increased crypt length and width, and fewer lineage-traced Lgr5+ cell-derived clones.
Muscle stem cell aging: Marked by increased inflammation, impaired self-renewal, decreased MuSC numbers, and changed interacting cell types.
Skin stem cell aging: Leads to epidermal thinning, dermal atrophy, increased fragility, collagen biosynthesis decline, delayed wound healing, and adnexal dysfunction.

Allogenic stem cell transplants
Advantages:

Harvested from donors, eliminating the need for invasive collection from the patient.
Good safety profile.
Practically unlimited source if mesenchymal stem cells are used.
Immediate availability.
Suitable for patients with genetic-related diseases.

Disadvantages:

Minimal risk of infection transfer if donors are not properly screened.
Risk of tumors when embryonic stem cells are used.
Ethical concerns, particularly with embryonic stem cells.

Dr Penaranda emphasized the importance of knowing the source and screening process of stem cells used in allogenic transplants. Proper donor screening is crucial to minimize the risk of infection transfer and other complications.

Xenogenic stem cell transplants
Advantages:

Harvested from animals, removing the need for invasive collection from the patient.
Practically unlimited source.
Immediate availability.
Can be used for patients with genetic-related diseases.

Disadvantages:

Negative misconceptions and significant religious and cultural restrictions.
Higher risk of infection transfer and complications.

Dr Penaranda highlighted the cultural and religious challenges associated with xenogenic stem cell transplants. In many regions, there are misconceptions about acquiring animal characteristics through these treatments, and religious beliefs may restrict the use of certain animal-derived products.

Practical considerations for stem cell transplantation
The decision to use a specific type of stem cell transplant depends on various factors, including the condition being treated, patient preferences, and the availability of suitable stem cell sources.

Autologous: Best suited for conditions without a genetic component and for patients who can tolerate the invasive collection process. However, the limited number and quality of stem cells in older patients can be a drawback.

Allogenic: Offers a more readily available and diverse source of stem cells, making it suitable for a broader range of conditions, including those with a genetic component. Ensuring proper screening of donors is essential to mitigate risks.

Xenogenic: While it provides an almost limitless source of stem cells, the cultural, religious, and infection risks must be carefully considered. Advances in screening and safety protocols are necessary to enhance the viability of this option.

Current trends and future directions
Research is increasingly focusing on allogenic and autologous transplants, with xenogenic transplants facing more skepticism due to cultural and ethical concerns. Bone marrow remains a primary source due to its high replication activity and yield. However, future advancements may enhance the practicality and safety of other sources.

Dr Penaranda stressed the importance of rigorous screening and ethical consideration in the application of stem cell therapies to ensure the safety and effectiveness of these therapies.

As stem cell research continues to evolve, the potential for these therapies to revolutionize regenerative medicine is immense. However, it is essential to navigate the ethical, cultural, and practical challenges to fully realize the benefits of stem cell transplants.